This is the case insert that everyone around your shop borrows from old cases, but never puts back. Always in short supply, the insert eliminates your having to place an engine mount nut by hand behind the oil cooler. It’s almost impossible to achieve. VW, in their infinite wisdom, put a steel insert in the case mounting hole behind the oil cooler, allowing you to use a bolt inserted from the transmission side, then into the block. If your engine case is ’71 and later dual relief, the hole is probably already oversize, and you can pull the insert in with a few washers and 10mm bolt. You can also install the insert into earlier cases by drilling an oversized hole. Made in China. Sold each.