The 30W Anti Explosion Horn Speaker has obtained an explosion-proof certificate and has a device to prevent static electricity. It can be used in flammable and explosive warehouses such as oil refineries, synthetic ammonia, paint shops and other horns. The explosion-proof certificate is very important. Without a certificate, even if the explosion-proof performance is better than the one with the certificate, it still cannot be regarded as an explosion-proof speaker. This is like an unlicensed driver for 40 years, he cannot be regarded as a driver. There are two types of explosion-proof certificates: one level and two. The general explosion-proof speakers can only be used on the ground. If it is underground, it requires first-class, not many in China. 30W Anti Explosion Horn Speaker is your good choice.