Woodpeckers Precision Woodworking 851 Square 8-inch x 5-inch, Wall-Mountable, Imperial Imperial Version All 851 Squares come in a custom-fitted case The blades on both squares are  thick and the handle is a full Squares are accurate to within .001 inch or less along the full length of the tool We even mill a notch at the inside corner of the square so you can zero-out your layout line all the way to the edge of your work