The SMART FIT support is the clamp block that all AR15 owners will need. Thanks to its design, it adapts and attaches to all AR15 magazine wells (223rem / 5.56mm) with its adjustment handle. It ensures that the weapon is held perfectly in place in a vice without damaging it, allowing you to carry out any maintenance work. It can be inserted into the magazine well from below, to work on the inside of the weapon, or from above, to work on the underside of the lower block. It comes with a pivot lock accessory that keeps the weapon open in two parts, freeing your hands to work on the chamber or barrel.