Explosion proof exit signs are class 1 division 1 or class 1 division 2. You know the difference for division 1 and division 2 are the presenting frequency for ignitable gas or vapor, if the gas and vapor present abnormally, you can choose class 1 division 2, if the gas and vapor present normally, you can choose class 1 division 1.Today, with the development for explosion proof technology, most explosion proof exit signs are class 1 division 1 to cover the class 1 division 2.