Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4336729.

This is a telescope T adapter for astrophotography using the eyepiece projection method. One one side it has M42x0.75 thread to connect to your T ring of choice for your camera. The other end press fits over a 32 mm Plossl eyepiece (or any 40 mm diameter eyepiece). The adapter is long enough to allow proper focus on my Orion XT8.

Moon photo taken with this adapter and Nikon D7200 on an Orion XT8.