The ST-VC3 valve is designed for loss-free filling and emptying of refrigeration and air conditioning systems. It allows the service hose to be connected without having to break the seal of the system, which minimizes refrigerant leakage. Main features: Loss-free filling – maximum reduction of refrigerant loss. Angular design – convenient operation with compact service connections. Pusher mechanism – precise opening of the valve available in the system. Tight PTFE (Teflon) seals – high chemical resistance and durability. Full 5/16″ SAE compatibility – designed for modern HVAC systems.