This quality precision machined thread adapter allows you to use a device threaded 5/8-24 to fit 3/4-24 threads. The adapter is threaded 3/4-24 on the inside (female threads) and has 5/8-24 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. Engraved. The best price and quality for a 3/4x24 to 5/8x24 adapter in the world.