Function:
1. WIDE RANGE OF USES Works with all kinds of telescopes, mirrors, refractors, for dobsons, for mak cas and for SCT, all you need to do is measure your telescope tube size and choose the appropriate mask size.
2. Provide the telescope with the best focus: the mask eliminates the guesswork of focusing and even overcomes viewing conditions to give your telescope the best focus quickly and easily.
3. 3 METAL POSTS The mask holds the telescopic tube gently and firmly with three metal posts. These metal posts come with scratch resistant silicone covers to protect the surface of your telescope. This prevents slipping while keeping the mask perfectly centred.
4. 3 Post Installation & Lightweight Design Thanks to this 3-post mount, the mask stays centered while accommodating a wider range of telescopes. The Bahtinov telescope focus mask is lightweight, so you dont disturb the balance of the scope.
5. Scope of application: the outer diameter of the Bahtinov focus mask supports the telescopic lens in the range of 100-140mm (there is a 1-2mm error due to manual measurement).

Specification:
Item Type: Telescopic Focus Mask
Material: acrylic.
Thickness: approx. 2 mm.
Color: As picture show
Approximate weight 38 g / 1.3 ounces.
The outer diameter size range of the telescopic lens is supported: approx. 100-140 mm / 3.9-5.5 inches (there is a 1-2 mm error due to manual measurement).

Package list:
1 x Bahtinov mask.
3 x mounting accessories.