NEW and Improved Gen2 �" Picatinny Rail Riser 5.2" Length is Picatinny / MIL-STD 1913 Standard profile and is lighter than the previous generation. Works on AR15/M4 platforms as well as any other firearms platforms with a Weaver/ Picatinny/ MIL-STD 1913 rail. This riser helps with getting low mounted optics and raising the optic up another � of an inch to a more comfortable cheek rest and shooting height. The rail has a hollow channel through the length to make it lighter and for some firearms act as a see-through sight channel to use the iron sights. Black Anodized Aluminum Construction Mounts with two Allen head bolts, mounting tool included.