... flame retardant, insulation, corrosion protection, waterproof, light weight, good air-tightness good properties. Cylinders work pressure,30Mpa .back frame for ... protect time.Mask(Drager):adopt double frilled edge sealing, good air tightness, spherical surface window, vison is wide, the clear ... need any tools.GA124-2004"positive pressure type fire air respirator"standards Contained breathing apparatus