The thread adapter is supplied with a special tool for mounting it on the camera. Once mounted, your other Leica correction lenses can be mounted on the M10. The Thread Adapter also enables the use of the Leica Angle Finder M and the viewfinder magnifiers on the Leica M10. The thread adapter and mounting tool are supplied in a Leica SD case for safekeeping when not in use.
Leica M10 eyepiece thread adapter