The makers of the Ultra Square claim that it can reduce plate layout time by half. They may be right: Marking a plate for studs and joists is a breeze with this tool. Just clip your tape measure to the extended edge guide, and hook the end of the tape over the end of the plate. Then pull the tape and the square as a unit along the plate. The slots in the square are configured so that the 3/4-inch on-center correction is done automatically. The square measures 41/2 inches across, so you can mark up to three adjacent studs at once. That comes in handy when laying out window openings and wall corners. The Ultra