Diesel Duty Performance Oil Filters A. 1" outside, 3/8" inside nut/ratchet drive for easy removal. B. Heavy-duty 600lb. canister C. Heavy-Duty coil spring on diesel applications D. Wire-backed media provides strength E. NF21 synthetic composite material provides maximum engine protection with minimal flow restriction F. Heavy-duty center tube provides maximum flow G. Anti-backflow valve to reduce damage during cold starts H. Heavy-duty .100"-thick base plate for extra strength I. Heavy-duty Nitrile rubber gasket for a leak-free seal