The Accu-Shot Monopods are designed to add stability and provide easy elevation adjustment for bi-pod equipped rifles. The Monopods attach to the rear sling swivel stud of most rifles, or the optional AR-15/M1-A adapter for military type rifles (A2 stocks only). The "Original" Monopod has a lockable elevation adjustment made by rotating the neoprene body of the monopod - each full rotation is equivalent to five inches of movement at 100 yards. This is a well-made, easy to install accessory suitable for shooting off the bench or on the ground. Each model features a lock ring to lock the elevation in place. Quick Knob model allows fast adjustments and has 3.5"-4.65" Mfg: Accu-Shot