The cantilever mount is designed for mounting telescopic sights with 30mm tubes onto a flattop style AR-15 rifle. The 3-inch offset of this cantilever mount positions the scope in a forward location, allowing the correct eye relief and head placement on an AR-15. This cantilever mount will work best with scopes having 4 inches (101.6 mm) or more of eye relief (if less than 4 inches (101.6 mm), use the model with 2 Inch offset).
The cantilever ring mount positions the center of the riflescope tube at a height of 1.47 inches (37.34 mm) from the base. Weighs 8.4 ounces / 238 g.