The Baader 1.25x Glasspath Corrector is designed for use with the MaxBright II and Mark V Binoviewers. It features a Zeiss dovetail ring on one end for direct adaption to the binoviewer. This can be swapped to a T2 (M42 x 0.75) thread by removing the lens from the body for direction connection to a T2 diagonal or nosepiece.
As the name suggests, it corrects the glass path through which light passes through the binoviewer's prisms, removing the chromatic aberrations introduced by the additional optical elements.
It also moves the focal point significantly, adding approximately 20mm of focus. When mounted in front of a star diagonal, an extra 15mm of focus is added. This is useful for telescopes which have limited backfocus.