Check the listing for details. Celestron C-11 Bahtinov Focus Mask Special split Cap Fit Bahtinov for Hyperstar. Condition: New. Listed at 26.00 USD. Please read, there may be different types and sizes of this model. Fir Celestronc11. And is split for Telescope with Hyperstar or without. . I can easily change measurements if need changes to fit yours just let me know sizes in millimeters. Can buy this one and message me the measurements you need it changed to and that's the one Ill send. Thanks. Bahtinov Focus Mask for Telescope - Celestron C-11. From Spencer 3D SLIDE ON. 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. If want in a different color I can make in several other colors just message and ask me. New Design c11 w Hyperstar split design, New design. SHIPPING CHARGES ARE SLOWLY CHANGING! MOST ITEMS THAT WAS FREE SHIP WILL BE CHANGING OVER TO CHARGED SHIPPING TO THE BUYER, DUE TO INCREASE CHAEGES OF SHIPPING AND SHIPPING SUPPLIES. BUT THIS WILL ALSO MEAN LOWER PRICES ON THE ITEMS, AND MORE SHIPPING OPTIONS, AS WELL AS FASTER SHIPPING OPTIONS. THIS ALSO MEANS MORE ITEMS AVAILABLE FOR INTERNATIONAL SELLS.