... Instrument 4.The Function of Non-Return Valve Visual Adjustable Auto Filling Valve, Water Heating Systerm, Refrigeration, Air Conditioner and ... is convenient.With the function of non-return valve,hand stop valve, diaphragm is larger than the same kind products ... valve consist in pressure reducing valve, stainless steel filter, shut-off valve and a check valve.With visual design, installed on the water ...