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 105 to 150 mm
The masks grip the telescope tube gently but firmly with three metal posts which have non scratching silicon sleeves; protect you valued telescope surface; Prevents slippage; Allow the mask to remaining perfectly central because of this 3 post mounting
The control box requires a standard 9V battery to operate; The 9V battery goes into the battery compartment in the rear of the control box; which can choose speeds from coarse to very fine with the adjustable speed control knob on the box
Accufocus electronic focuser cannot be used on Maka; DOB type telescopes and telescopes with APO two speed focusing; but only on telescopes with single speed focusing such as some brands of refractors and reflectors in the 60 to 127 mm range