These will help you keep an eye on what's going on inside your motor. We have them in 4 inch and 6 inch. The 4 inch we have with and without provision for screw on filter. 6 inch we have with no screw on filter. These are setup for -12 o ring in and out. They also have a -3 o-ring port for -4 turbo feed or oil supply also. Have block adapters for bbc/sbc, sbf/chrysler, or early LS. This is the filter the pros use and will help you keep up on your engine program, no more messy cutting of oil filters!