The most difficult part of cutting wood to length with a circular or jig saw, is accurately aligning the saw blade to our pencil mark. Unlike a standard square, the Kreg Square-Cut™ features an adjustable guide arm which locks-in your saw’s unique base-to-blade offset, allowing you to instantly align your saw blade to the pencil mark and make perfect 90 degree cuts, time after time. The Square-Cut's adjustable guide arm compensates for the length from the blade to the edge of your base plate, and can be set to match any circular saw or jig saw. What does this mean for you? No more eye-balling the blade on the pencil mark or using your tape measure to get the correct set-back… just faster results, fewer mistakes, and less aggravation.