It was an Earl's Performance #516 Oil filter bypass adapter purchased from Summit racing, I don't recall were the unit was made. Had it on my B18 engine for many years, with inlet plugged and a VDO oil temp sender in the outlet port. Never created a problem or worry. On initial installation of the new B20, with 1800E oil pan I did not have the proper oil temp sender adapter for the oil pan and continued to use the Earl's adapter. With the low oil pressure and oil light coming on everything was checked, and a 2nd new oil pump and new seals was installed, but same problem. Than timing cover was removed to check if the gear oil nozzle was in place, which it was. At about this time I was able to obtain the proper oil temp sender adapter for the 1800E oil pan, so the Earl's adapter was removed, oil and filter changed, and at start up oil pressure reading are at 60psi. Now after numerous trips all seems to be normal and I am able to monitor oil pressure and temperature.