Sighting-in made simple. 1) Aim at a fixed point (target or bull's eye) and fire a 3-5 shot group to establish your point of aim. 2) Clamp the gun in the vise and use the adjustments to center the reticle on the point of aim. 3) Without moving the gun or the vise, use the adjustments on the sight to move the reticle to the center of the group. This has an integral level. Bingo! You've just mechanically and optically aligned the points of aim and impact. Allows you to sight in your pistol in 5 shots or less Heavy steel base Non-marring, closed-cell foam rests won't damage your pistol Integral level Base is 10.5" wide Adjusts from 4.5-7.75"l. and 9.75-10.5"h.