Provides extra rail room for rear Back Up Iron Sights (BUIS) when using the StrikeFire red dot along with the VMX-3T magnifier. The cantilever ring will move the StrikeFire forward about one inch. Will work with most 30mm red dot sights. Positions red dot sight at either an absolute co-witness height or a lower 1/3 co-witness height. Mfg: Vortex Optics
