S8182 astronomical telescope M54 extension bucket rear intercept adjustment ring 4-20MM optional photography extension bucket

S8182 M54 * 0.75 extension bucket rear intercept adjustment ring 4-9MM optional

Outer diameter: 60mm

Pitch: 0.75

Outer screw length: 3mm

Internal thread length:

4mm-3mm

5mm-4mm

6mm-4.5mm

7mm-5.5mm

8mm-6mm

9mm-7mm

10-20-8mm

Black matte black treatment