Valterra 400-S PVC Air Check Valve, Clear, 1-1/2" Slip, Repairable Schedule 40 PVC construction for strength and resistance to corrosion and mild chemicals EPDM seal for resistance to water and oils Maximum pressure rating of 150 psi Spring tension of 1/4 lb. for secure closure of valve 1-1/2" slip and 2" spigot connection