The Vixen Optics T-Ring Adapter for Sony Alpha Cameras is meant for use with their various methods of mounting SLR cameras to the rear of their telescopes, but obviously they can be used for anyone who has a T-mount system lens and wants to mate it to their SLR camera without any real trouble. Many, if not most, of the inexpensive T-mounts will get stuck to the camera or lose adhesion to the lens;
With the Vixen Optics models, the superior workmanship really limits the incidence of these kind of annoyances. The T-mount lens and T-mount combination will only work on the camera with the camera in the "M" manual exposure mode. Additionally, the most advanced metering modes usually don't work with the T-mount.