The adapter fittings are compatible with female 10AN ORB (O-ring boss) ports which are threaded 7/8-14 and feature a chamfer for the O-ring to seal against. Because the threads on these fittings do not seal, no PTFE or thread sealant should be used. The O-ring should be lubricated with engine oil. ORB ports are an industry standard and found on many automotive plumbing products, including Radium products such as Catch Cans(all versions), AOS-R, and Fuel Filters. These are perfect for finshing a custom installation of Radium catch cans or fuel filters. All fittings include O-rings, excluding the 7/8"-14 Banjo Fittings which include crush washers.