Compatible with Celestron C8/C8HD/C925/C11HD; also compatible with SKYRVER 80ED/100ED/102ED/130APO. Made of premium aluminium alloy, solid construction is wearable and durbale for years of use. With the finder scope dovetail base, you can install finder scope on your telescope; multifunctional dovetail base fits any diameter telescope tube. Dovetail base fits M3, M4, M5 or 1/4" threaded screws to assemble for your optical tube; just put it on the optical tube and tighten the screw. CNC machining ensures sleek surface and precise cutting of rail, it fits your telescope perfectly. Material Aluminium Alloy Colour Black Width of internal slot 5.1mm Horizontal length of internal slot 37mm Vertical length of internal slot 35.5mm Type Doveta.