Just twist the upper knurled locking ring and your 1.25″ eyepiece, camera nosepiece, or laser collimator is centered precisely in your 2″ focuser, and securely gripped by a polypropylene compression ring, which will not scratch or mark your equipment. Standard 1.25″ adaptors use a thumbscrew which pushes the inserted accessory to one side when tightened. Not so with this clever adaptor. And wait, there’s more....Unscrew the knurled locking ring to expose a male T-thread on the lower black barrel, which conveniently functions as a 2″ prime focus (2″ to T thread) adaptor by itself. So you’re actually getting two adaptors for the price of one! You’ll want one for every scope!