Be straight to a T. The STAEDTLER T-Square's head rests against the edge of your drawing or drafting table to give you a straight horizontal line. Use set squares with the t-square to get a variety of straight lines at different angles. This t-square features a fixed wooden head on a hardwood body for strength and rigidity, and raised see-through acrylic edges to prevent smudging and surface scratches. The blade measures 36" (90 cm) long and 2.5" (6.5 cm) wide.