The Adams Arms P-Series M-Lok Rail was designed for Adams' P-Series rifles. It has a rigid and ergonomic design and features that make this the best choice for everyday enthusiasts, avid shooters, 3-gun competitors. It utilizes a full length Picatinny rail, M-Lok attachment points at 3, 6, and 9 o'clock, four QD attachment points, and ergonomic finger grooves. This 15.5" model has a black finish and is compatible with Adams Arms' low profile piston systems and most standard mil-spec AR-15 rifles.