The LT129 Cantilever QD CompM2 mount pushes your Aimpoint out over the D-ring...leaving more room behind to mount your NV stuff or even an Aimpoint 3X Magnifier. The base has a built-in watertight storage compartment for an extra battery...comes in handy. The LT129 positions the centerline of the optic 1.7" above the top of the rail. Like all LaRue mounts, it is precision-machined out of bar-stock aluminum and matt black anodized to provide a durable non-reflective surface finish. The locking LaRue Speed Lever provides outstanding return to zero; the optic can be removed, and replaced, without loss of zero.