... apply to underground work, entertainment, fire disaster, toxic gas environment, etc. 1. Product FeaturesZH30/ZH15 self-rescuer is ... when take place catastrophe and cause poisonous gas or hypoxia (gas blasting, coal and gas blasting, fire etc). This is a ... Respirators apply to underground work, entertainment, fire disaster,toxic gas environment, etc.2. Structure and PrincipleZH30/ZH15 is oxygen ...