Use as a standard magazine well block to hold in your bench vice. The block can hold the lower receiver in the upside down position for easy removal  of your pistol grip. Hold right side up to work on your lower receiver internals, and trigger. Our block also has a special setting for use as a hammer drop block while held right side up in a vice. The function of the drop block setting is to let the hammer fall on a soft Teflon insert to reduce wear and damage on vital parts such as your receiver and trigger parts. With the entire gun assembled slide the block into your magazine slot, or with just your lower receiver slide in the block to either location for use holding your lower right side up, or upside down.