Update for 2017: Now compliant with ISSF Rules!
This stable and adjustable mounting device is used to fit a lens from a pair of shooting glasses on their rear sight. The lens can be moved closer to, or further away from the eye. Once fixed in place, the correction lens therefore stays in exactly the same place, perfectly positioned in relation to the sighting line. This approach offers a number of benefits for shooters who use relatively weak lenses and otherwise have no need for spectacles.
As the illustration shows, the Monocle mono-lens holder is fitted between the rearsight and rear iris using the tool supplied. It comprises an adapter fitting, a rod holder with clamping mechanism, a support rod for the lens holder and a lens holder.