Troy industries fixed rear battlesights' is a permanent rail-mounted alternative to a standard a2 sight that allows limitless mounting options on all-length rails with a serrated ramp to eliminate glare.Provides a continuous zero unflinching durability.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.Fits all m4 m16 ar15 ar10 variants and other firearms that have a flat top receiver or removable carry handle.*note- 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.Type: Fixed RearFrame Material: AluminumFrame Color: BlackFirearm Fit: AR-15 AR-10 M4 M16Style: FixedFront Material: N/AFront Color: N/AFirearm Type: AR-Platform