Diagonal Prism Optical Prism inside rather than a mirror which makes your image clear and sharp
1.25 inch 45 degree mirror star diagonal for any telescope with 1.25 inch connector ;not suitable for Newtonians
More comfortable viewing orientation as you observe from above; filter thread for any 1.25 inch filter;. Accepts standard 1.25 inch eyepieces
Please be assured that these focusing masks will work excellently for both reflectors and refractors with whatever focal length; All you need to do is to measure your telescope tube size and choose the right size of the mask
They are made from 2 mm thick laser cut abs; Securing screws are capped with soft plastic so they do not damage your telescope; These Bahtinov masks are adjustable to fit a wide range of optical tubes; They have adjustment latitude of about 195 to 240 mm