Model No. FSCV15TB;Quiet sump pump threaded check valve;The unique spring loaded flapper eliminates the water hammer noise of standard check valves;100% Stainless steel clamps included-fits 1-1/2″ pipe;Threads directly into the pump’s 1-1/2″ Outlet to connect it to a 1-1/2″ Pipe;Pre-drilled weep hole to eliminate air lock that may occur in bottom suction pumps