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Amazon.com : Astromania Bahtinov Mask Focusing Mask for Telescopes - FM100mm for a Tube Outer Diameter (OD) from 105mm-150mm - can be Mounted with The Brass Screws Inside or Outside The drawtube :
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Amazon.com : Starboosa Bahtinov Mask Focusing Mask for Telescopes - 140 Bahtinov Mask for a Tube Outer Diameter from 138mm to 173mm (5.43" to 6.81") - can be Mounted with Brass Bolt
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Astrozap Focusing cap with built-in Bahtinov focusing mask for 80mm refractors and similar scopes | Astronomics.com
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Farpoint Adjustable Tri-Bahtinov Mask - 15 Inch to 18 Inch OTAs - Camera Concepts & Telescope Solutions
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