Can be moved or taken off without permanent modification to the firearm; Snag-free apertures at factory height; Machined from hardened Aircraft Aluminum with stainless steel components; Finished in MIL-SPEC hardcoat anodizing; Designed to work on same-plane rail systems only; Will not work with a railed gas block that is higher or lower than the receiver; Front sight must be mounted at the same height plane as the rear sight; Railed gas blocks that are lower than receiver height will not zero properly; Black Finish