... Pa 4.shortage years :5 5. light 1. Product FeaturesZH30/ZH15 self-rescuer is a equipment whom work ... reacting, and be used to provide the wearer with oxygen when exploring a coal mine or in ... opening air sac quickly, utilize air pressure combine with CO2 and water vapor, through chemistry , made into ... Certificate issued by CQST. (CQST is mutual recognition with Norway’s NEMKO, Germany’s PTB, America’s ...