1. New dual helix focusing device
2. High precision double helix focusing device, used for guiding mirror/viewfinder mirror interface
3. Solutions for slow focusing telescopes or telephoto lenses
4. The item is made of all metal and is sturdy and durable
5. Accuracy: 0.1mm
6. Interface: 1.25 inches, with M42 * 0.75 internal thread
7. Main image interface: M42X0.75
8. Focusing stroke: 10mm
9. Minimum length: 56mm
10. Maximum length: 66mm