Rotation Indicator
Schmidt & Bender Klassik 8?56 scopes include a rotation indicator, created to give a visual reference of the position of the reticle within its adjustment range. The display contains a black dot in a white window that shows the reticle position.
When mounted, this allows the gunsmith to verify if the black dot is close to the letter ?M?, indicating that a sufficient adjustment range in both directions is available for zeroing.