The Novagrade T-Mount Digiscoping Adapter has everything you need to couple your camera to the eyepiece of your spotting scope. Simply screw the filter ring adapter onto the filter thread of your lens, attach the T-mount, and press the T-mount's polymer compression ring over the eyepiece of your scope. The compression ring ensures a perfectly centered image as well as a mar-free interface to the eyepiece—a simple twist and it is locked on. Six compression rings are included for eyepieces ranging from 39 to 60.75mm.