... design, crush-proof, good impermeability, safe and stable.HYZ4 cooling canister chamber equips with drainage, which protects against the ... breathing system resistance.Excellent cooling performance, light and easy to carry.Adjustable constant flow ... of Flow1.6±0.2L/minDemand Valve≥80 L/minBypass Valve≥80 L/minVent Valve Maximum Value400~700PaBypass Valve Minimum ...