Replaceable plastic check valve with 1/2" M.P.T. (part# 5322222). Direct OEM replacement. UV & impact resistant. Resistant to road salts & acids. Paintable. NSF 61. Key lock. Cut out dim: 4-3/4" H x 4-1/4" W. Outside dim: 6-1/2" H x 6" W. Collar depth: 1-1/2". Polar White