EXHEAT Industrial's HFT thermostats are supplied in weatherproof or explosionproof enclosures to complement our heaters. All thermostats are certified for use in hazardous areas where the atmosphere is classified as a Zone 1 or 2 (IIA, IIB, IIC) gas group. The HFT is designed for the temperature control of work or storage areas, in conjunction with a hazardous area air heater.