M42 * 0.75 Extension set 3/5/7/10/12/15/20/30mm svbony usb camera loosen the three screws to

loosen the three screws to free the inner ring before attaching the adapter

Blocking: Blocks unwanted light from UV to IR wavelengths

Improve working efficiency

Additionally

M42 * 0.75 Extension set 3/5/7/10/12/15/20/30mm svbony usb camera loosen the three screws toM42 * 0. 75 Extension set 3 5 7 10 12 15 20 30mm When you cannot get to the right focal plane for focusing with a camera or eyepiece. This extension tube kit solves this problem. You can use this extender with any camera or eyepiece or with various adapters. The M42 * 0. 75 threads on both ends make it extremely versatile. Use this extender for obtaining the correct image scale or for the exact spacing required for a reducer or field flattener. You