This is the Du-Bro 393 8-32 Threaded Inserts (4pcs)

These brass threaded inserts are the perfect way to put threads into wood and mount engines to wood mounting rails. Threaded inserts make a simple and effective way to make wing hold downs and can be used where blind nuts are hard to fit.

These useful fasteners can also be used in woodworking and furniture building. 4/pkg