YHM is very pleased to offer the flagship Black Diamond XL Carbine Top End. The Diamond forearm bridges the gap between the upper receiver and hand guard and is marked for position on all 4 sides to easily mount accessories in the same position after removal. YHM's diamond pattern in the hand guard reduces weight and blends perfectly with their diamond fluted barrels! This top end contains all internal parts, so simply drop it onto your existing lower and hit the range!