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.
Provides lower 1/3 co-witness mounting height of 40 mm. Will work with most 30 mm red dot sights. 0.35 (lbs) weight.