Adjustable Tension Mechanism to increase or decrease the drag of the stock along the buffer tube. Precision CNC machined receiver mount with pivoting sling loop. Scorpion recoil grip. Scorpion Razorback recoil pad. Adjustable Soft Touch Polymer cheekrest. Polymer over-molded forend. Sleek forend integrated heatshield. Military Type III anodized 6061 T6 aluminum magazine tube is precision CNC machined and holds five shotgun shells. Military Type III anodized 6061 T6 aluminum magazine follower is precision CNC machined. Magazine tube tri-rail provides 3 picatinny rail mounting locations. Manufactured in the USA. Fits Benelli M4 Shotguns with 18.5 inch barrel. Does not fit Benelli M4 NFA Versions (14.5 inch barrel).