1. Scope of Application: 1.25 inch to C CS mount adapter fits any telescope C mount (male thread) telescope eyepiece changer with a 1.25 inch eyepiece tube.
2. 1.25 Inch Mount and M25 Thread: The 1.25 inch mount is suitable for filters, focus reducers, and extenders. M25 external thread is suitable for C mount or CS mount camera lenses.
3. Aluminum Alloy Material: Made of black anodized aluminum alloy, which is , . The adapter is fully threaded inside to reflections of stray light.
4. Internal and External Thread Specification: External thread specification is M25x0.75mm (commonly known as C mount, CS mount thread). Internal thread specification is .6x0.6mm.
5. Adapter Size: External thread depth is 5mm / 0.2in, internal thread depth is 4mm / 0.16in, outer diameter of mount is about 1.25 Inches (31.6mm±0.1mm), overall length is 30mm / 1.2in.

Specification:
Item Type: 1.25 Inch Mount to C CS Mount Adapter
Material: Aluminum Alloy
External Thread Specification: M25x0.75mm (Commonly Known As: C Port/CS Port Thread)
External Thread Depth: Approx. 5mm / 0.2in
Internal Thread Specification: .6x0.6mm
Internal Thread Depth: 4mm / 0.16in
Outer Diameter of Mount: Approx. 1.25 Inches (31.6mm±0.1mm)
Overall Length: Approx. 30mm / 1.2in
Color: As Pictures Shown
Weight: Approx. 16g / 0.6oz

packing list:
1 x Adapter