Check the listing for details. Fine Focus Knob for Celestron 8" and 9.25" SCT Telescope Version 2. Color: Galaxy Black, Condition: New. Listed at 18.99 USD. Fine Focus Knob for Celestron 8" and 9.25" SCT - Version 2 This large 70 mm (2.76 in) diameter knob slides over your stock focuser giving you fine focusing detail focusing & fast coarse focusing at the same time! Stock focus knob alone: 5 mm turn = 26° focus change.Fine focus knob: 5 mm turn = 8° focus change. Larger focus knob perimeter gives you the finer focus for planets and stars that the stock focus is lacking. Over 3 times finer focusing than the stock focus knob. Also the stock knob is always available at the ready for quick coarse focus changes. FITS: Celestron 8" SCT, Celestron 9.25" SCT telescopes.As the product pictures suggest, your focus knob should be black and made of rubber. This is not designed to fit older all-metal focus knobs. Inside diameter: 22mm, fits +/- 2mmOutside diameter: 70mm Images shown on Celestron Evolution 8" - Color is Galaxy BlackIf you want a different color or size let us know the you order and we'll send you a list of more colors available. *Celestron Fine Focus Knob v2 by yellowhornet is licensed under the Creative Commons - Attribution license. Thingiverse thing:3565319 Condition is Brand new. Made in USA