B&G 4V is a 1/8"IPM coin operated manual air for venting radiators in hot water heating systems. 150 psi maximum and 250 degree F.Specifications:Size:1/8"Thread Type: MaleMax Pressure (PSI):150Height: 5/8"Width: 5/8"Connection Type:ThreadedMax Temp (F):250°FMaterial: Stainless SteelThis vent is specially designed for the new types of radiators. An important feature is that it projects only slightly, being almost flush with the radiator.