Material: This heavy duty square blade is made of high quality stainless steel, durable and rustproof. Size: This carpentry square is 12 inches long and the blade is accurately marked. Wide Application: This combination square set is ideal for marking 45 and 90 degree angles, and can also work as a handy gauge for transferring precision angles and other measurements; essential for use in your rafter, deck, stair and roofing projects, and other general carpentry operations. This T-ruler allows you to make quick and accurate marking and measuring.