Grovtec US Inc GTSW241 Picatinny M-Lok Rail AR Style 5 Slot Aluminum 3.5" L 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. It easily accommodates different-length attachments and provides for a wide adjustment of eye relief. Included is the associated hardware for install. Type: Picatinny Rail Model: AR Style Dimensions: 3.5" L Size: 5 Slot Material: Aluminum Finish: Black Hardcoat Anodized