Hornet-35 300W Airplane Cockpit Engine Compartment Heater This heater is waterproof and certified to meet U.S. Coast Guard ISO 8846 requirements. The thermostat is hermetically sealed and set to maintain an average temperature of 65* The safest self temperature regulating heating module is used. You can not buy a safer heating element. This is the only heater on the market that uses a safe, non-conductinve, fire-rated fiberglass housing the fans are 50,000+ hour, long life, brushless, ball bearing, DC type that are waterproof