This single-port sandwich plate makes it easy to connect your Accusump (sold separately) to your engine with no drilling or tapping required. Simply take off your old oil filter, install this adapter like you would install a new filter, and install a fresh oil filter on the adapter. The feed line from your Accusump screws right in the 1/2 NPT female port. Do not use a check valve with this adapter. Has 3/4" -16 thread and a 2-5/8" standard O-ring.