Check the listing for details. Fine Focus Knob for Celestron C11 Telescopes 70mm Dia- GLOW IN DARK VERSION. Color: white and glow in dark green, Condition: New. Listed at 11.24 USD. Goes over existent knob, has 3 bolts and nuts design to tighten securly to the knob. Gives an bigger knob to more easily tune your Celestron C11. Also there is an colir black and blue glow in dark options also available for this knob. Or any color you want just let me know. Fine Focus Knob for Celestron C11 70mm Dia-fits over existing knob. Condition is "New". Shipped with USPS First Class Mail. Made and designed from 3D printing software, fitted and tested. Made from Spencer-3D, made in United States. Comes in glow in dark greeb but can have in other colors when requested. Just message if need a different color or need a custom part. This knob is 70mm diameter and is perfect for fine tuning its sometimes hard to do with a small knob. Faster tuning when it counts. 2 to 3 day U.S. shipping.