Homewerks VCK-P40-B6B In-Line Check Valve, Female Thread x Female Thread, PVC Schedule 40, 1-1/4-Inch Schedule 40 construction Fits both Schedule 40 and Schedule 80 pipe O-ring seal, spring loaded poppet, and stainless steel spring Threaded end complies with ANSI B1.20.1 Not for use with compressed air