Flush Hex Drive Threaded Inserts are installed the same way as any other threaded insert. They do not have a lip near the head, so they can be installed completely flush with the surface or even a little countersunk. Flush drive threaded inserts are generically referred to as Type E insert nuts.
Play video
How to Use & Install Helicoil Thread InsertsInstalling Threaded Inserts in Wood Without Special Tools