This durable, all steel sight mounts on the same plane as the rear sight to give you a backup iron sight. The sight folds out of the sight line with the push of a button and flips and locks in the deployed position with ease. Mounts quickly and easily with the included thumb screw. Accepts all standard AR sight posts and hardware (included).The Gas Block Height sight mounts to a railed gas block and is a great option to back-up or cowitness with optics.