These are Great Planes Brass Threaded Inserts (4-40)
The perfect way to put threads into wood and mount engines to wood mounting rails. Threaded inserts make a simple & effective way to make wing hold downs.
Can be used where blind nuts are hard to fit
Comes in a Parts-Pak clear plastic box with resealable lid
One year quality guarantee
Includes: (4) Threaded Inserts
Requires: 3/16 Drill Size (package says 1/4 but that is too large)
Standard Slotted Screwdriver (-)