RHZK Breathing Apparatus is a kind of aotomatically open type breathing device.Mainly applicable in the fields of firefighting,chemical industry,ships,petroleum and mine industries.Full facemask,good air tighteness,wide vision,equipped with new type air supplying valve,light and stable performances.The pressure releaving valve unit is equipped with a residual air volume warning system that can send out acoustic signals to warn the rescue workers to leave the site in time.