"Alumicolor has a full line of Professional T-Squares with a 2" wide extruded aluminum blade. Calibrations are made using the Alumicolor photo anodizing process giving all our products a smooth, tick-free finish that will not wear. The black ABS plastic heads are lightweight and nearly unbreakable. The heads are secured with 5 screws instead of rivets. Unlike the Standard T-Square, the Professional aluminum blades have channeled backs that glide easily on drafting tables. Available in a wide range of sizes. 12-Inch Drafting T-Square 18-Inch Drafting T-Square 24-Inch Drafting T-Square 30-Inch Drafting T-Square 36-Inch Drafting T-Square 42-Inch Drafting T-Square 48-Inch Drafting T-Square Choose from a wide-variety of Colors: Silver Professional T-Square Gold Professional T-Square Purple Professional T-Square Red Professional T-Square Blue Professional T-Square Green Professional T-Square Black Professional T-Square The aluminum shaft is made in El Salvador and plastic head is made in the USA. Assembled in the USA. Alumicolor products are made with the highest quality extruded aluminum. All Alumicolor T-squares feature ultra-smooth inking edges with exact calibrations that will stand the test of time."