For rock solid stability and dead on accuracy in a fixed sight, Fixed Battle Sights get the job done. This fixed rail mounted alternative to a standard A2 sight allows limitless mounting options on all length rails with a serrated ramp to eliminate glare. For use on same plane rail systems only. This sight is not with a railed gas block. Sight is 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 Hardened T6 aluminum with stainless steel components Rock solid stability and dead on accuracy Made in the USA.