Developed for use on the flat ARCALOCK rails such as the 12″ Universal M-LOK Keymod and MPA that do not have a built in stop. Slides on from the end of the rail does not clamp “over” and can be locked in any position on the rail. 1-1/8″ tall from bottom of rail. Grooved to aid in gripping the barricade. Uses a pinch clamp design and also a set screw to engage one of the ARCALOCK cuts to guarantee no slippage. 3/32 Wrench included and required to move clamp not designed to be a moveable stop.