These stainless-steel precision machinist squares are perfect for the professional machinist, meticulous wood worker, or the DIY perfectionist. They are cut and ground from a solid blank of 6mm (0.220") thick stainless steel. Squares are thick enough to stand on their edges with no support. All faces and edges are ground and lapped for straightness and parallelism. There is a groove milled in the inner corner to provide clearance for burrs and debris. Manufactured to strict German DIN 875/0 standards and guaranteed square to within tight tolerances. All squares come in wood storage boxes.