This quality precision machined thread adapter allows you to use a device threaded 3/4-24 to fit 11/16-24 threads. The adapter is threaded 11/16-24 on the inside (female threads) and has 3/4-24 threads on the outside (male). It is machined in one turning operation to guarantee concentricity to your threads. Full engagement flats for easier removal and disassembly. Imitation adapters often have very tiny wrench flats which can round off and become useless. Black Oxide finished and is engraved. The best price and quality for a 11/16x24 to 3/4x24 thread adapter in the world.