... flame retardant, insulation, corrosion protection, waterproof, light weight, good air-tightness good properties. Cylinders work pressure,30Mpa .back frame for ... having the advantage that other brands haven't. Such as: the air demandis to a maximum of more than 500 liters), ... protect time.Mask(Drager):adopt double frilled edge sealing, good air tightness, spherical surface window, vison is wide, the ...