CORPORATE PRESENTATION 2010

1. CORPORATE PRESENTATION 2010

2. OVERVIEW • Sonim Technologies • Who we are • What we stand for • Our experience • Market Size • In the news • Experts on the blue/grey collar market • Our understanding • Interacting with customers • The RPS standard • Our products • XP1 • XP3 Enduro • XP3 Quest Pro • XP2 Spirit • XP3 Sentinel • XP1300 CORE • XP3 Enduro Zone 2 • Solutions • PTT • Lone Worker • MRM • Atex • Market Approach • Service and Warranty • Economic Model • Guerilla Marketing • POS/Incentives • Training

3. SONIM TECHNOLOGIES

4. Who we are Sonim Headquarters, San Mateo California • Founded in 1999, now with over 150 employees worldwide across 15 locations • Dedicated to the Blue and Grey collar market with over 10 years of experience providing hardware and software solutions • Recognized leader of the ruggedized GSM mobile segment • Targeting all who work and/or play in truly extreme environments • Profitable, privately funded by leading Venture Capital Firms Canada Sweden UK Russia Germany Netherlands Slovak Republic France China Spain Italy UAE Colombia Brazil India Chile Argentina New Zealand

5. WHAT WE STAND FOR People who work and play hard in extreme environments have always shared one thing in common – no phone was made just for them. No phone company ever though to built a phone rugged enough for those whose relationship with the earth and its elements was extreme and for whom a phone was an equipment and not an accessory. Sonim is committed to delivering the highest quality rugged phones bundled with tailored applications that give people who work and play hard in extreme environments the security to make clear calls, anytime, under any conditions. Impermeable to life’s harshest elements they are simply the longest-lasting phones, guaranteed. To meet the exacting requirements of our active users – we follow the Rugged Performance Standard: 12 dimensions upon which every Sonim is constructed to ensure the maximum level of ruggedness. So each and every Sonim phone can withstand conditions such as water submersion, extreme temperatures, shocks, drops and dust.

6. OUR EXPERIENCE Countries where Sonim phones are sold Telenor & Telisonera Orange & Vodafone Mobile operators who have tested and approved Sonim phones Vimplecom TDC KPN T-Mobile Vodafone Telefonica Orange Optus Vodacom & MTN Entel Vodafone Vodafone • 350,000 handsets sold to date in over 50 countries • tested and accepted by top mobile operators worldwide • 9 models released to date

7. MARKET SIZE There are currently over 6.7 billion people on this planet Of those individuals, there are 4 BILLION mobile phone users Of those users, 2 BILLION of them live in industrialized nations Of those 2 billion people, 100 million (5% of the market) are people who work and/or play in extreme environments These 100,000,000 people, THE CONSTRUCTION WORKERS THE SHIPPERS AND FISHERMEN THE OIL RIGGERS THE TRUCKERS THE FIREFIGHTERS AND POLICE THE PLUMBERS/CARPENTERS/ROOFERS ETC. THE MILITARY THE INDUSTRIAL WORKERS HAVE NOT BEEN A PRIORITY OF THE MAJOR MOBILE PHONE MANUFACTURERS

8. IN THE NEWS • Wired Magazine http://www.wired.com/gadgetlab/2009/07/rugged-cellphones/ "Nokia’s latest 3720 Classic cell phone … nothing compared to the Sonim XP3 Quest 2.0, a mobile phone that can withstand being flung across the room or used as a hammer — and can be heard perfectly over the noise of a jackhammer." • PCWorld • http://www.pcworld.com/article/170706/tough_tech_rugged_gear_that_can_survive_almost_any_calamity.html "Though Sonim only recently made its phones available in the United States, the company's reputation precedes it. Sonim's phones have survived elephants, cars, bullets you name it--causing buzz all over the Internet and on YouTube." • Financial Times http://www.ft.com/cms/s/0/2678d6c6-5c1e-11de-aea3-00144feabdc0.html?nclick_check=1 • ... this impressive handset should appeal to anyone who lives, works or plays in an extreme – or just dirty or difficult – environment, even with its expected“ • Gizmodo, http://gizmodo.com/5342669/sonims-absurdly-tough-xp3-lands-in-the-us-400-unlocked#comments "After the beering, the hammering, the shooting, and the elephant stomping, it's fair to say that, on the toughness front, Sonim's gotten their point across. Now, after months of teases, you can actually buy the XP3, unlocked, for $400."

9. EXPERTS IN THE BLUE/GREY COLLAR MARKET

10. OUR UNDERSTANDING • Sonim possesses a superior understanding of the blue/grey collar market due to years of constant dialogue with relevant enterprises around the world Benelux DACH Nordic UK/Ireland Australasia MEA • City Power South Africa • Dubai Police Force • KOC Kuwait Oil • Transnet Railways • G4 security • Premier Foods • A1 road works fulfillment • APCOA Corporate group • Hessen (Germany) forest department • Cologne Port Authority • Thyssen Krupp Steel • Swiss Railroads • New Zealand Defense Force • Kiwi rail • Water care Services • NZ Coastguard • Schipol Airport Amsterdam • Heijmans Construction • LOT (Dutch agriculture) • Zorg Care Center Netherlands • Svenska Foder (Farmers Union) • Stockholm Coast Guard • National Police Force • Uppsala Ambulance Force

11. CONSTANT DIALOGUE WITH CUSTOMERS Feedback from customers has shown us that blue/grey collar workers/enterprises need much more than just drop proof and water proof phones. They need a reliable tool that helps them be more productive. Our customers said: In response we: • developed the 12 element Rugged Performance Standard (RPS) Click below to watch video • http://www.sonimtech.com/rps.php "Just because a phone looks rugged, doesn't mean that it's meant for me. I need a phone that was really designed for people like me. This means extra loud speakers for use in noisy environments and an extra long battery life so I never have to worry about charging my phone in the field. “ • Developed a tailored application and provisioning support capability for selected enterprise applications "I need a device that will allow me to track and correspond with my team while they are in the field" • investing over $ 100 Million in • R&D on Materials and Equipment "I've broken my phone numerous ways, dozens of times, and each and every time I lose a day or more of productivity because I don't have a mobile phone that works properly and need to get it replaced."

12. When we set out to build the Sonim phone there were no standards for a phone this rugged. So we had to create them. Compiled from over ten years of feedback from customers that lead extreme and rugged lifestyles, the Rugged Performance Standards consist of 12 benchmarks of endurance that set the standards for which all ruggedized devices must live up to. ACCESSIBLE KEYPAD ACCESSIBLE KEYPAD EXTRA-LOUD SPEAKER EXTRA-LOUD SPEAKER PROTECTION FROM DUST PROTECTION FROM DUST PROTECTION FROM WATER PROTECTION FROM WATER PROTECTION FROM DROPS EXTRA-LONG BATTERY LIFE PUNCTURE PROOF RESISTANT TO PETROLEUM OILS 3-YEAR UNCONDITIONAL GUARANTEE RESISTANT TO SHOCKS & VIRBATIONS RESISTANT TO EXTREME TEMPERATURES RESISTANT TO EXTREME PRESSURE

13. EXTRA-LONG BATTERY LIFE A licensed contractor is often far away from an electrical/charging source, and spends days at a time away from power outlets using several GPS based applications that drain the battery faster than under normal usage. To accommodate for this, Sonim has equipped its phones with top of the line lithium-ion batteries (1850 mAh) which provide up to 18 hours of talk time or 1500 hours of standby

14. ACCESSIBLE KEYPAD Construction workers need to be able to make a call at a moment’s notice under the roughest conditions without removing their work glovesThe keys on Sonim’s phones are larger and more widely spaced than those on the average mobile phone to make it easier to for people who are wearing gloves, or whose hands are wet or slippery, to dial.

15. EXTRA-LOUD SPEAKER Paramedics need to regularly call for assistance on a mobile phone to relay critical information clearly-- even in noisy, urban settings. Sonim phones are equipped with custom-built speakers capable of producing sounds at 110db – over 45% louder than more than other mobile phones. This is louder than standing next to a snowmobile revving its engine (100db).

16. PROTECTION FROM DUST Wood mill workers often find their mobile phones covered in layers of sawdust at the end of the day. Dust, sand and other micro-particles are electronics killers -- and the smaller a device’s components the more damage they can do.Ports and entry points on the Sonim phones are specially sealed to prevent the intrusion of industrial micro-particles. Sonim phones are IP-67 rated: impervious to dirt, dust, and micro-particles.

17. PROTECTION FROM WATER Dock workers need a phone that can withstand being submerged in sea water after falling overboard. Sonim phones are specially engineered for use around salt and fresh water. Sonim phones is waterproof - they can be fullysubmersed in over 1 Meter of water for 30 minutes.Rated IP-67, signifying submersibility and durability in water after numerous tests.

18. PROTECTION FROM DROPS Forestry personnel often drop their mobile phones from extreme heights. Unlike other handsets, a Sonim phone will quickly bounce back to life when dropped, never skipping a beat. Sonim phones can be dropped from a height of over 2 Meters onto concrete from any angle

19. RESISTANT TO SHOCKS & VIBRATIONS Electricians need to be able to toss their phone in the tool box at the end of the day, let it rattle around in the back of the truck on the way home, and be assured the phone will continue to work like a tool the following morning. Ordinary phones can stop functioning when exposed to sudden jolts or an extended series of vibrations. Sonim uses a process called under filling which glues the phone’s internal components to the PCP board to prevent any component from becoming dislodged or disconnected after a fall or shock. To accommodate for this, Sonim has vigorously tested it’s the its phones, subjecting them to OVER 2,000 RANDOM VIBRATIONS at UP TO 4G of force.

20. RESISTANT TO EXTREME TEMPERATURES Military personnel in Afghanistan and workers fixing a pipeline in the arctic temperatures of Russia have one thing in common: they need a phone that can withstand the most extreme of temperature climates. Typical electronic devices don’t work well -- or at all -- when exposed to very cold or very hot temperaturesTo accommodate for this, Sonim has built its phones to be fully operational in temperaturesranging from -20°C to +55°C.

21. RESISTANT TO EXTREME PRESSURE Workers in the freight and transportation industry require a phone that can withstand regular mishaps on the job, such as being accidentally crushed by cargo or run over by machinery. And whether by accident or design, numerous Sonim customers have exposed their phones to extreme amounts of pressure over the years. Sonim phones are tested against OVER 1 TON OF PRESSURE to ensure that whatever you subject a Sonim to, it will survive the punishment.

22. PUNCTURE PROOF Workers in the steel and metal industry are constantly surrounded by sharp and heavy objects that would puncture the average phone. While we can’t claim that our phones are bulletproof, they are nearly everything else proof. To prove it, we subject the housing of our handsets to over 5 Joules of energy. Thus whether you drop a box of nails or your claw hammer on your Sonim, you can rest assured that the phone will be fully resistant to any punctures. The extremely scratch resistant Gorilla Glass Lens can withstand up to 2J of impact energy without a blemish.

23. RESISTANT TO PETROLEUM OILS The auto mechanic often uses his phone while taking apart and reassembling an automobile’s engine. As a result, by the end of the day, his phone is often covered in petroleum oil. Since so many of our customers work outdoors or otherwise expose their phones to all sorts of interesting messes, they need a phone that can survive exposure to petroleum oil and oil cleaning solutions.To insure that our phones are fully operational in even the dirtiest of environments, we expose them to over 500 different chemicals.

24. 3-YEAR COMPREHENSIVE WARRANTY Here at Sonim, we believe that you can’t really say that your product is rugged, unless you stand behind your product. That’s why all of our phones are backed by an industry leading 3-YEAR COMPREHENSIVE WARRANTY. That means that Sonim will cover any accidental breakage or malfunction of the phone within three years.

25. OUR PRODUCTS

26. SONIM PRODUCTS OUR PRODUCTS PARTNER PRODUCTS

27. Sonim XP1- no longer available RPS COMPLIANCE EXTRA-LONG BATTERY LIFE 1100mAh with 5 hrs talk and 200 hrs standby time ACCESSIBLE KEYPAD Widely spaced keys for ease of use with gloved hands EXTRA-LOUD SPEAKER Capable of producing up to 110 db of noise PROTECTION FROM DUST Non-porous casing blocks entry of most micro particles PROTECTION FROM WATER Water resistant to exposure from any direction PROTECTION FROM DROPS Withstands 1.2 m drops on concrete RESISTANT TO SHOCKS&VIBRATIONS Built to withstand random vibrations up to 2G RESISTANT TO EXTREME TEMPERATURES Works in environments ranging from -20°C to 55°C RESISTANT TO EXTREME PRESSURE Withstands up to 1/2 ton of pressure PUNCTURE PROOF Withstands up to 2J of impact energy RESISTANT TO PETROLIUM OILS Not tested 3-YEAR COMPREHENSIVE WARRANTY FEATURES PERSONAL AREA NETWORKING Bluetooth 1.2 compatible

28. Sonim XP3 Enduro - no longer available RPS COMPLIANCE EXTRA-LONG BATTERY LIFE 1180mAh with 6 hrs talk and 320 hrs standby time ACCESSIBLE KEYPAD Widely spaced keys for ease of use with gloved hands EXTRA-LOUD SPEAKER Capable of producing up to 110 db of noise PROTECTION FROM DUST Non-porous casing blocks entry of micro particles PROTECTION FROM WATER Water submersible to 1 meter for 30 minutes PROTECTION FROM DROPS Withstands 1.6 m drops on concrete RESISTANT TO SHOCKS&VIBRATIONS Built to withstand random vibrations up to 4G RESISTANT TO EXTREME TEMPERATURES Works in environments ranging from -20°C to 55°C RESISTANT TO EXTREME PRESSURE Withstands up to 1 ton of pressure PUNCTURE PROOF Withstands up to 3J of impact energy RESISTANT TO PETROLIUM OILS Tested against 500 chemicals 3-YEAR COMPREHENSIVE WARRANTY FEATURES PERSONAL AREA NETWORKING Bluetooth 1.2 compatible WEB BROWSER Opera Mini included @

29. XP3 QUEST RPS COMPLIANCE EXTRA-LONG BATTERY LIFE 1850mAh with 18 hrs talk and 1500 standby time ACCESSIBLE KEYPAD Widely spaced keys for ease of use with gloved hands EXTRA-LOUD SPEAKER Capable of producing up to 110 db of noise PROTECTION FROM DUST Non-porous casing blocks entry of micro particles PROTECTION FROM WATER Water submersible to 1 meter for 30 minutes PROTECTION FROM DROPS Withstands 2 m drops on concrete RESISTANT TO SHOCKS&VIBRATIONS Built to withstand random vibrations up to 4G RESISTANT TO EXTREME TEMPERATURES Works in environments ranging from -20°C to 55°C RESISTANT TO EXTREME PRESSURE Withstands up to 1 ton of pressure PUNCTURE PROOF Withstands up to 5J of impact energy RESISTANT TO PETROLIUM OILS Tested against 500 chemicals 3-YEAR COMPREHENSIVE WARRANTY FEATURES SCREEN TOUGHNESS Shock resistant screen GPS TRACKING Equipped with a turn-by-turn navigation application RUGGED 2MP CAMERA

30. Sonim XP3 Quest Pro RPS COMPLIANCE EXTRA-LONG BATTERY LIFE 1850mAh with 18 hrs talk and 1500 standby time ACCESSIBLE KEYPAD Widely spaced keys for ease of use with gloved hands EXTRA-LOUD SPEAKER Capable of producing up to 110 db of noise PROTECTION FROM DUST Non-porous casing blocks entry of micro particles PROTECTION FROM WATER Water submersible to 1 meter for 30 minutes PROTECTION FROM DROPS Withstands 2 m drops on concrete RESISTANT TO SHOCKS&VIBRATIONS Built to withstand random vibrations up to 4G RESISTANT TO EXTREME TEMPERATURES Works in environments ranging from -20°C to 55°C RESISTANT TO EXTREME PRESSURE Withstands up to 1 ton of pressure PUNCTURE PROOF Withstands up to 5J of impact energy RESISTANT TO PETROLIUM OILS Tested against 500 chemicals 3-YEAR COMPREHENSIVE WARRANTY FEATURES FEATURES FEATURES FEATURES FEATURES SCREEN TOUGHNESS Extremely scratch and shock resistant Gorilla Glass screen GPS TRACKING Equipped with a turn-by-turn navigation application JAVA APPLICATIONS ENHANCED Includes Trimble Outdoors, amAze GPS navigation & SonimMail RUGGED 2MP CAMERA SCREEN TOUGHNESS Extremely scratch and shock resistant Gorilla Glass screen GPS TRACKING Equipped with a turn-by-turn navigation application JAVA APPLICATIONS ENHANCED Includes Trimble Outdoors, amAze GPS navigation & SonimMail RUGGED 2MP CAMERA SCREEN TOUGHNESS Extremely scratch and shock resistant Gorilla Glass screen GPS TRACKING Equipped with a turn-by-turn navigation application JAVA APPLICATIONS ENHANCED Includes Trimble Outdoors, amAze GPS navigation & SonimMail RUGGED 2MP CAMERA JAVA JAVA JAVA

31. Sonim XP2 Spirit RPS COMPLIANCE EXTRA-LONG BATTERY LIFE 1200mAh with 8 hrs talk and 428 hrs standby time ACCESSIBLE KEYPAD Widely spaced keys for ease of use with gloved hands EXTRA-LOUD SPEAKER Capable of producing up to 110 db of noise PROTECTION FROM DUST Non-porous casing blocks entry of micro particles PROTECTION FROM WATER Water submersible to 1 meter for 30 minutes PROTECTION FROM DROPS Withstands 2 m drops on concrete RESISTANT TO SHOCKS&VIBRATIONS Built to withstand random vibrations up to 4G RESISTANT TO EXTREME TEMPERATURES Works in environments ranging from -20°C to 55°C RESISTANT TO EXTREME PRESSURE Withstands up to 1 ton of pressure PUNCTURE PROOF Withstands up to 5J of impact energy RESISTANT TO PETROLIUM OILS Tested against 500 chemicals 3-YEAR COMPREHENSIVE WARRANTY FEATURES SCREEN TOUGHNESS Extremely scratch and shock resistant 1.5 mm Gorilla Glass lens Tough Materials Dual Injected Shell (hardened rubber, fiberglass & nylon) Magnesium Core Multimedia Player Video and MP3 RUGGED 3MP CAMERA 3MP still and video protected by Gorilla Glass

32. Sonim XP3 Sentinel RPS COMPLIANCE EXTRA-LONG BATTERY LIFE 1850mAh with 18 hrs talk and 1500 standby time ACCESSIBLE KEYPAD Widely spaced keys for ease of use with gloved hands EXTRA-LOUD SPEAKER Capable of producing up to 110 db of noise PROTECTION FROM DUST Non-porous casing blocks entry of micro particles PROTECTION FROM WATER Water submersible to 1 meter for 30 minutes PROTECTION FROM DROPS Withstands 2 m drops on concrete RESISTANT TO SHOCKS&VIBRATIONS Built to withstand random vibrations up to 4G RESISTANT TO EXTREME TEMPERATURES Works in environments ranging from -20°C to 55°C RESISTANT TO EXTREME PRESSURE Withstands up to 1 ton of pressure PUNCTURE PROOF Withstands up to 5J of impact energy RESISTANT TO PETROLIUM OILS Tested against 500 chemicals 3-YEAR COMPREHENSIVE WARRANTY FEATURES SCREEN TOUGHNESS Extremely scratch and shock resistant Gorilla Glass screen GPS LOCATION Equipped with A-GPS capabilities and location reporting LONE WORKER APPLICATION Dedicated color coded button and keys RUGGED 2MP CAMERA

33. Sonim XP1300 CORE EXTRA-LONG BATTERY LIFE 1750mAh with 18 hrs talk and 800 standby time ACCESSIBLE KEYPAD Widely spaced keys for ease of use with gloved hands EXTRA-LOUD SPEAKER Capable of producing up to 110 db of noise PROTECTION FROM DUST Non-porous casing blocks entry of micro particles PROTECTION FROM WATER Water submersible to 2 meters for 30 minutes PROTECTION FROM DROPS Withstands 2 m drops on concrete RESISTANT TO SHOCKS&VIBRATIONS Built to withstand random vibrations up to 4G RESISTANT TO EXTREME TEMPERATURES Works in environments ranging from -20°C to 55°C RESISTANT TO EXTREME PRESSURE Withstands up to 1 ton of pressure PUNCTURE PROOF Withstands up to 5J of impact energy RESISTANT TO PETROLIUM OILS Tested against 500 chemicals 3-YEAR COMPREHENSIVE WARRANTY TOUGH MATERIALS Dual injected shell (hardened rubber, fiberglass mix) IP-68 RATED FOR 2M SUBMERSIBILITY Fully submersible to 2M for 30 Min in water NOISE CANCELLATION Omni-directional microphone with noise cancellation MULTIMEDIA PLAYER Video and MP3

34. XP3.10 Enduro - Zone 2 Level of explosion protection: · Ex II 3G Ex ia IIC T4 Main features: · Tri-band GSM 900/1800/1900 · MIL-810F compliant · IP-67 Certified · GPRS · Bluetooth 1.2 · WAP Ex II 3G Ex ia IIC T4 Temperature Class: Maximum surface temperature exposed to gas in case of malfunction is 135°C Protection Type: Intrinsic Safety Device Group: Non-mining devices Category: Can be used in Zones 2 and 22 Atmosphere: Gas Explosion Group: Most dangerous group (e.g. hydrogen)

35. SOLUTIONS

36. SOLUTIONS Sonim is continuously striving to set the standard for what it means as a company to be a provider of a full portfolio of applications and devices important to the blue/grey collar industries. How does Sonim make its users safer and more productive? Communication: Work group Push-To-Talk (PTT) Implementation Productivity: Industry Leading Mobil Resource Management (MRM) Applications Safety: • Cutting Edge Lone Worker & Man Down Functionality. • A range of “Intrinsically Safe” handsets, suitable for operation in potentially explosive/hazardous environments, certified to ATEX or NEC standards.

37. PUSH-TO-TALK (PTT) Mobile Network PTT uniquely allows for increased worker productivity across workforces as it enables almost instantaneous communication across the field with multiple parties instead of the standard one-to-one communications that take place through a regular GSM call. . Teams in Field Field Control / Office Fixed Network Wireless Network PoC DispatcherPoC sessions viaVoIP from desktopto teams in field • Sonim XP1, XP3 • IP67 ruggedized • High-output audio • PoC button • Bright screen GPRS/UMTS/EVDO/WiFi/WiMAX IP VPN PoC AdministratorWeb-based toolfor workgroupadministration Hosting Centre XPS,EMS XPA, NTI

38. Mobile Resource Management Mobile Resource Management (MRM) applications allow companies to immediately locate and track their employees while in the field, thereby increasing their productivity and efficiency in work order management, job assignments, and clerical duties with respect to time cards and customer invoicing. MRM applications are most commonly used by Field Service and Utility workers. • Mobile Resource Management (MRM) • Allows for: • GPS-based Job Tracking • Work Order Management • Mobile Time Cards • Customer Billing • Geo-Fencing

39. LONE WORKER Lone Worker applications have been developed in response to many new pieces of legislation currently being passed in the EU and the US, which mandate that companies must provide their "lone workers" with a "lifeline" to the outside world in case they are in need of assistance. Sonim has taken this one step further, by pairing this application with backend monitoring centers that allow the user to be constantly tracked and to be able to reach out for help in mere seconds should they ever need to. Lone Worker applications are currently being utilized primarily by the security industry, but have also found their niche in the utility and mobile healthcare sectors as well. • Lone Worker Protection Capabilities • Dedicated red risk side buttons triggers emergency notification, tracking and call to emergency call centre, via native firmware • Amber and green buttons trigger dedicated Java ME applications for customized monitoring states • Man down sensor (3 axis accelerometer) & monitoring software • Loud speaker phone & omni-directional microphone for red risk monitoring

40. ATEX phones, otherwise known as Intrinsically Safe devices, have been specially manufactured in such a manner to ensure that when taken into fuel-rich or explosive environments, the phone will not emit or discharge any amount of energy which may cause an explosion. These devices are commonly required by law in: oil refineries and fields, pharmaceutical plants, processing mills, and etc. ATEX Device Group I = Mining Equipment II = Non-Mining Equipment Explosion Group I = Methane IIA = Propane IIB = Ethylene IIC = Hydrogen Application Atmosphere G = Gas D = Dust Explosion Protection II 2 G Ex ib IIC T4 Temperature Class (°C)* T1 = 450 T2 = 300 T3 = 200 T4 = 135 T5 = 100 T6 = 85 Type of Ignition Protection ia = Intrinsic Safety (Required of Zone 0 Devices) Ib = Intrinsic Safety (Required for Zone 1 & 2 Devices) n = Normal Operation Under Normal Conditions (Zone 2) Device Category 1 = Can be used in Zone 0 2 = Can be used in Zone 1 3 = Can be used in Zone 2 * Maximum surface temperature exposed to gas in case of malfunction