Threaded ring with M45 x 0.5 thread for the shortest possible adaptation of the
Hyperion Universal Zoom Mark IV on Zeiss Diascope Spotting Scopes FL 85 and FL
65;
Spotting scope side with Zeiss M45 x 0.5 thread, eyepiece side with retaining edge,
which attaches with the clamping ring of the Mark IV Zoom;
Enables extremely short adaptation (larger backfocus reserve) at
Focusing on infinity – important for spectacle wearers