... work, entertainment, fire disaster, toxic gas environment, etc. 1. Product FeaturesZH30/ZH15 self-rescuer is a equipment whom work under ... by chemical reacting, and be used to provide the wearer with oxygen when exploring a coal mine or in the environment where ... gas environment, etc.2. Structure and PrincipleZH30/ZH15 is oxygen candle born oxygen in early. After opening air sac quickly, utilize ...