"The Baader Planetarium Click-Lock Eyepiece Clamp (# T2-08) is a precision clamping eyepiece holder that enables you to insert your eyepieces or standard 1 1/4"" accessories anywhere within the ASTRO T-2 System, or for upgrading the stock holder supplied with telescopes. The Click-Lock clamp offers a brand new approach to eyepiece holders. Once you try one, you'll never go back to simple set screw or even captive brass clamp rings again! With a gentle twist of the outer ring, two special non-marring rollers cam into contact with the eyepiece and firmly lock it into the holder. The 3-point clamp action guarantees none of the eyepiece wobble common in all single screw clamps or Takahashi lockring style holders. The lack of a protruding lock screw also eliminates one of the annoying hassles of standard holders - no more contortions trying to trying to work your nose around an inconveniently positioned screw. The holder is precisely machined to fit your eyepieces with a minimum of slop, resulting in a close accurate fit that keeps your eyepiece properly centered on the optical axis. The long contact length of the cam rollers also makes this holder compatible with all grooved eyepiece barrels by bridging the groove. No more mismatch or hassle of unlocking from the groove. The secure grip of the cam lock makes the grooved barrels obsolete. On the front (input) side, the eyepiece clamp has an internal T-2 thread, to mate it to the other components of the T-2"