Lion Gears BM1205EXBT Hunting Club/Shooters Club/Bear Hunt/Wild Hunter Bridgemount Riser, Black.5"/5" System oriented design with under the rail opening-build a flexible and compact mounting System Robust and light-weighted design with steel-to-steel connection between thumb bolt and locking nut plate Precision Machined solid aircraft grade aluminum with hard Anodizing for tight tolerance and durability See-thru design with Pica tinny/Weaver mounting base