Collimation Knobs for Celestron 14" SCT (non-Nexstar). No Tools Needed! It''''s'' easy ... just grab a Bob''''s'' Knob and turn. You can even do it while looking through the eyepiece on most scopes. And you''ll never drop that pesky little Allen wrench or screwdriver in the grass again. Installation is a snap with included instructions, and you can undo the modification at any time. In 2003, Celestron changed the design of the C14 secondary collimation system. The new C14 scopes now come from the factory with three Phillips screws instead of the three Allen set screws used on the previous C14. Scopes with the old screws require a different set of Bob''''s'' Knobs (BK C14) because the screws are a different size and length.