Designed to fit Bresser, Omegon and Explore Scientific Newtonian reflectors that have internal threaded M54x0.75 focusers, the Alpine Astronomical Baader 2" ClickLock Eyepiece Clamp is a unique eyepiece mounting system that is superior to conventional mountings. Unlike compression ring and set screw holders, the ClickLock system uses three long roller bearings to hold the eyepiece firmly centered in place without marking or marring it, while eliminating the wobble and off-axis tilt. A simple 20° twist locks and unlocks the clamping system for fast eyepiece changes even while wearing gloves. There is no need to fumble with small set screws or for using excessive force and torque to hold the eyepiece in a fixed position.