Check the listing for details. Celestron 9.25" W/ Hyperstar Tri-Bahtinov Mask, Hinged Design! C9 Tri Bahtinov. Condition: New. Listed at 19.99 USD. Celestron 9.25" W/ Starzona Hyperstar Tri Bahtinov Mask, Hinged With 110mm I.D. Center hole Diameter, and 262mm O.D on mask, so it fits an Inner diameter on Telescope of 262mm. Bolts together, One as a pivot and other end bolts to stay shut once on telescope. Now upgraded and thicker mask to have more strength. This version is a Tri Bahtinov has 110mm inner diameter Hole so it will fit all types of Celestron 925 inch models, with a Hyperstar. check specifications and measurements before purchasing for your telescope. . This is meant for Celestron 9.25 inch with Starzona Hyperstar, or Hyperstar 4. And the regular version , if buying for regular version it may have some space in middle diameter hole and that is so it fits all versions. Special design to split apart and has bolt and nut hinge to pivot on your 9.25" telescope without taking off parts from Starzona Hyperstar . Comes with set of 2 bolts and nuts and Bahtinov mask. Can put on and off even easier. More options will be available for the Celestron 9.25" on my eBay Store. Tri Bahtinov Focus Mask for Telescope - Celestron Edge HD 9.25" or any Celestron C9, Celestron 9.25 inch Telescopes. This is meant for Telescope with Hyperstar so its spilt or Hinged so you dont have to take off Hyperstar to put on mask. Condition is New. Shipped with USPS First Class. Software Designed and tested. Works great with these and similar models. 3d printed and designed by Spencer 3d. As always fast USPS SHIPPING. 2 TO 3 DAY SHIPPING. BLACK . Other colors and types available just ask. Fits Celestron HD 8 Inch. If need a particular size message me, or if have questions.