Marketing InformationThe Apollo 61 Series ''''Soft Seat'''' Check Valve offer reliable tight shut-off protection against reverse flow and corrosion resistance using proven ASTM quality materials made in the USA. Ideally suited for hydronic heating and other low flow applications. Soft seat allows more resistance to vibration and may be installed in both horizontal and vertical upward flow applications.Bubble-Tight Shut-off, Ideally Suited for Gaseous ServiceEDPM Check Disc (61-500 Standard)Straight-Through Flow Minimizes Pressure Loss1/2 psi Cracking PressureMade in the USA