The picatinny riser mount mounts to an existing rail.It is crafted from cnc-machined aluminum and is easy to install without modification.It is ideal for mounting scoped but can be used for red dot sights as well.It works well on any ar-15 flattop.This 1-piece model has a 0.75" mount height.Length: 4"Type: Picatinny Riser MountModel: Riser MountFinish: Black Matte AnodizedMaterial: AluminumPieces: 1Gun Type: AR PlatformMount Type: Picatinny RailMount Height: 0.75"