This adapter fits any standard 1/2-28 TPI and changes the thread to 9/16-24 LEFT HAND! Black Oxide finished, wrench flats included. Turned on a precision CNC turning center so the part is guaranteed concentric to your threads. Beware that the thread adapter turns onto your existing threads that are 1/2-28 Right Hand, and the external threads are LEFT hand threaded. This makes it possible to unscrew the adapter from the host while tightening the attachment. Always exercise care when using reverse direction thread adapters.