The Leitz MacroLux (sold separately) is a powerful tool on the right lens. With the Duclos MacroLux Reduction Ring, you have the ability to use the Leitz MacroLux on lenses with an 80mm front diameter in addition to the standard 95mm that the MacroLux is designed for.
Simply insert the Reduction Ring into the rear of the Leitz MacroLux which will be held in place by tongue/groove design. Removing the insert is just as simple thanks to the tabs on the reduction ring.