This Celestron Sony E T-Ring attaches to Sony E-mount mirrorless camera bodies.  It has a 42 mm female diameter on one side and the proper bayonet flange mount on the other.  Please note that this T-ring only works with Sony E-mount mirrorless camera bodies.  It does not work with Sony A-mount cameras without adding an adapter from Sony to convert them to E-mount.  

To use this Sony E-Mount T-Ring, mount it on your Sony mirrorless camera instead of your camera lens. Just like changing a lens, line up the T-Ring to your camera’s lens mount. Push it in and turn until you hear a click. The T-Ring has a sturdy bayonet flange that locks for a secure fit. Once you attach the T-Ring to your camera, you’re ready to connect your telescope. The telescope side of the T-Ring has threads that accept a variety of M42 camera adapters, including the Celestron T-Adapter. The adapter you choose depends on the type of photography you wish to do.

The Sony E-Mount 42mm T-ring is machined aluminum black anodized. The internal surfaces are blackened and glare-threaded to provide the highest contrast. The T-Ring has a ribbed surface for a secure grip while threading/unthreading. The Sony E-Mount 42mm T-Ring is compatible with M42 x 0.50 (T-Thread) camera adapters.