If you attach an Aimpoint Comp M XD or M2 red dot sight directly to an M16/AR15 "flat-top" upper receiver’s integral rail using a conventional ring mount it will be far too low to acquire the red dot without front sight interference, no matter what type of cheek weld you adopt. Our Aimpoint Cantilever Ring permits mounting the Aimpoint Comp M XD or M2 directly to the receiver’s integral rail with the red dot positioned above the front sight post. Yet it’s still low enough so that our MAD or A2-Style Flip Up Rear Sights can be deployed directly through the Aimpoint’s optics should its battery fail. The GG&G Cantilever Ring is also designed to place the Aimpoint Comp M XD far enough forward so that a night vision monocular can be mounted to the rear in co-alignment and in conjunction with the Aimpoint’s night vision compatibility. The ring body has a built-in insulated spare battery compartment with a spare Aimpoint battery cap, located on the side for easy access.