Optimized for use with AR-15/M4 upper receivers; Machined from 7075-T6 High Strength Aluminum for durability; Single-piece billet aluminum construction enhances strength and rigidity; Mounting surface spans 7 picatinny sections with 4 shear lugs for secure attachment; Utilizes Geissele's nut and bolt method for 1,400 pounds of clamping force per nut; Capable of interchanging caps between base towers without loss of precision or return-to-zero; Available in Standard, Extended, and Hyper Extended lengths; Offered in black type 3 hard coat anodize or proprietary DDC (Desert Dirt Color) type 3 hard coat anodize