This is a high-profile railed gas block for the AR-15, machined from aircraft aluminum with a 0.750" journal. The integrated top Picatinny rail sits at sight height, leaving the block exposed for use with iron sights or accessories rather than tucked under a handguard. Mounting hardware and roll pin are included. Features: High-profile, sight-height design Integrated top Picatinny rail 0.750" journal Aircraft aluminum construction Mounting hardware and roll pin included Fits AR-15 barrels with a 0.750" gas journal. This is a high-profile block and is not intended to sit under a free-float handguard.