From A.R.M.S.:

One of the most versatile mounts on the market. Made of extruded aluminum with a Mil-spec black hardcoat.

The #5 Multibase is a Quick detachable, multiple eye relief mounting base that attaches to weaver type rail and flat-top receivers. The multibase is compatible with both weaver style rings and NATO STANAG mounts. It raises your sight platform 3/4" and features a spring loaded clamping bar and self locking captivated thumbnuts for solid, zero movement mounting to your existing rail. The #5™ multibase also features a see through channel for use with iron sights. Also available with Throw Levers® - see #63.

Weight - 5.2 oz
Length: Approx. 5"
Height: Approx. 3/4"