Daniel Defense's Rock & Lock Rail Mounted Front and Rear Sights are easy to install and are highly versatile. Their overall design provides an unobstructed sight picture, and are snag-free to reduce the chance of catching on loose clothing/equipment. These sights attache to the weapon via MIL-STD-1913 picatinny rail and secures itself with a slotted fastener threaded into a self-locking stainless steel thread insert. The Rock & Lock Rail Mounted Sights have also been optimized for use with compact weapon lights with a concave radius on either side of the front sight as a place to rest your thumb for fast and ambidextrous light activation. Daniel Defense Rock & Lock Fixed Front/Rear AR-15 Iron Sight Combo Set 19-088-09116