Looking for rock solid stability and dead-on accuracy in a fixed sight? Troy Industries Fixed BattleSights get the job done. This permanent, rail-mounted alternative to a standard A2 sight allows limitless mounting options on all-length rails with a serrated ramp to eliminate glare. Provides a continuous zero, unflinching durability and peace of mind. The Troy Rear Fixed Rail 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. Features: - A permanent rail mounted alternative to a standard A2 rear sight or carry handle. - Provides constant access to fixed sights that continuously hold their zero. - Extremely durable and reliable providing peace of mind. - The most rugged fixed rear sight available. - Hardened T6 aircraft aluminum construction with stainless steel components. - Fits all M4, M16, AR15, AR10 variants and other firearms that have a flat top receiver or removable carry handle. - Flat Dark Earth