Farpoint 72mm Camera Filter Bahtinov Mask – FarpointAstro
Bahtinov mask - Wikipedia
William Optics Bahtinov Focusing Mask Cap for Z61 Telescopes Only - Red # CPBM-61RD
Amazon.com : Astromania Bahtinov Mask Focusing Mask for Telescopes - FM180mm for a Tube Outer Diameter (OD) from 195mm-240mm - can be Mounted with The Brass Screws Inside or Outside The drawtube :
Dwarflabs DWARF II 2 Telescope Bahtinov Mask 1.25 - Etsy
Amazon.com : Astromania Bahtinov Mask Focusing Mask for Telescopes - FM60mm for a Tube Outer Diameter (OD) from 65mm-100mm - can be Mounted with The Brass Screws Inside or Outside The drawtube :
Bahtinov Focusing Mask 100x100mm fits Cokin Z Series - Etsy