GrovTec's Picatinny M-Lok Rail is precision CNC machined from lightweight, solid aluminum with Type III Black Hard Anodized finish. The MIL-STD 1913 Picatinny rail pattern allows mounting a variety of lasers, sights and scopes or other accessories. Size 9 Slot Type Picatinny Rail Model 3.8 Inch 9 Slot M-Lok Series M-LOK Material Aluminum Dimensions 3.80"