A rifle scope base adapter rail in anodized matte black finish for Ruger rifle models listed below, which have two ring notch cuts on top of the frame. The adapter rail clamps onto the ring-notch cuts and allows use of Picatinny- and Weaver-style scope rings and also mounts red dot sights with Picatinny- and Weaver-style mounts. No drilling is needed. The rail has 12 ring slots, which make it easier to set up eye relief and find more desired placement of scopes or red dot sights. It also has a see-through U-shaped opening that might allow use of iron sights depending on the type of scope or sight installed. Machined from extruded aluminum alloy. Mounting screws are included with the unit. Does NOT include scope rings Rail type: Picatinny and Weaver Number of ring slots: 12 Overall length: 4 3/4 Finish: Anodized matte black Weight: 2.6oz * When mounting the rail onto the rifle, try using the different holes and align the mounting screws to the ring notch cuts for the best fit since the adapter mount is designed for use with different models. Flip the mount from end to end if necessary. Check alignment of the rail to the center line of the barrel before tightening the clamping screws. Use blue thread locker on the screw threads, check the screws often, and be sure they stay tightened when using. * Always be sure to unload the chambers and practice safe gun handling when mounting the rail. * The adapter rail is compatible with Ruger 96/44, M77/22, M77/44, and M77/ML, Mini-14 and Mini-30. Also fits the Ruger 580 Ranch, which is the Mini-14 whose serial number starts with 580. * On some Ruger models, the U opening on the mount might not be large enough to allow the iron sights to be fully visible.