One of the goals of the CSF 911/930 Engine Oil Cooler was to have a single unit that could fit both older (65-71) and newer models (72-89). The solution may seem simple, but engineering the two upgraded stainless steel fittings so there was no oil flow restriction took some extra design work. CSF took some inspiration from the CSF 911/930 Turbo Fender Oil Cooler (CSF #8168) using a similarly designed "Widemouth Fitting". The threaded M30 "Widemouth Fitting" for the 65-71 models maintains the optimized inner diameter (ID) of the oil pipe to maximize flow through the oil system. The "Widemouth Fitting" offers 50% greater flow capacity over the OEM connection. The machined in-house Stainless Steel fittings offer increased strength and durability over the OEM Aluminum slip-on tube (72-89 models) and threaded M30 fitting (65-71 models). Both OEM connections are common sources of leaks. CSF also includes two high quality copper crush washers to offer the best possible seal and prevent any leaks.