Description:
1. The function of the extension cylinder is to increase the distance between the lens and the imaging screen. It has a T2 interior thread and a T2 exterior thread for solving spacing problems in astrophotography and eliminates a range of focusing problems.
2. Fully metal construction and anodizing aluminum process, durable for long time use.
3. Use this extension tube for getting the correct image scale or the exact spacing required for reducers or field flatteners.
4. Includes 8 different lengths - 3mm 5mm 7mm 10mm 12mm 15mm 20mm 30mm. The required spacing can be achieved by combining several extenders of differing lengths, you can use 1 pc, 2 pc, 3 pc of the extension rings as you like

Specification:
Length:3mm 5mm 7mm 10mm 12mm 15mm 20mm 30mm(optional)
Material: aluminum alloy
Internal thread: M42*0.75mm
External thread: M42*0.75mm
Color: black