SING F LTD Bahtinov Mask Lightweight Acrylic Telescope Focusing Mask for Tube Outer Diameter from 60mm to 90mm for Reflector Refractor Dobsonians

Made of premium acrylic, the telescope focusing the mask is strong and durable, reliable and long-term.. The telescope fish bone plate is a suitable different telescope, such as a reflector, a refractor, for dobsonians. For Mak Cas, for SCT, you only need to measure the size of the telescope tube.. The mask gently holds the telescope tube with three metal columns. These metal columns have a silicone cover with scratch resistance to protect the surface of the telescope. This can prevent slipping and make the mask completely in the middle.. The scorched fish bone board overcomes the visual situation and can easily and easily provide a perfect focus for the telescope.. The outer diameter of the mask supports the telescope mirror within the range of 60-90mm (there is an error of 1-2mm in manual measurement)