Sometimes 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 M48*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 can reach the extension length required by combining several extenders of different lengths.