1. It is widely used in flammable and explosive gas environment such as oil exploitation, refining, chemical industry, offshore oil platform, oil tanker, etc. It is also used in flammable dust places such as military industry, port, grain storage and metal processing;
2. Applicable to Zone 1 and Zone 2 of explosive gas environment;
3. Applicable to IIA, IIB, IIC explosive gas environment;
4. Applicable to areas 21 and 22 of flammable dust environment;
5. Applicable to the temperature group is T1 ~ T4 / T5 / T6;
6. Used to perform signals or warnings.