Anti-Drain-Back Valve, Epoxy coated for corrosion resistance Backed by Sierra's industry leading warranty, Engineered with premium grade materials that will excel in the extreme marine environment Field-tested and approved, Heavy-wall steel canister for further corrosion protection GM Engines (Long), Manufactured to meet or exceed OEM specifications High-efficiency filter media that meets or exceeds the OE's filtration Thread Spec: 13/16" x 16 NPT or 206mm x 16 NPT