Ideal for use on Orion ED80 and ED100 as well as Sky Watcher equivalents. The bracket has a clever two-screw spring-loaded adjustment system that allows precise and quick calibration with the main instrument - robust enough to remain in perfect collimation after the telescope is stored ready for the next observing session. Fits all standard dovetail shoes found on Orion, Sky Watcher, Helios, Celestron, Konus and many other scopes.