3 inch long x 7/8 inch wide MIL-STD Rail Kit

".........The JCS MIL to MIL 3" long rail kit. This universal rail kit can be mounted in many configurations. Provide 4 rail locating positions: on-center, 3/8 offset, 7/8 offset and 90 degree mount to end of clamp. This rail is machined from solid aluminum and black anodized. We call our rails the "JCS 7/8 Modified-MIL-SPEC-1913 Accessory Mount". It accepts any quality accessory that requires a "Weaver" style, "Picatinny" style, or "7/8" mount. Securely installs with a phillips medium (#1 size) screw driver and provides a rigid accessory mount........."