6” LENGTH – Aluminum drafting triangles are useful tools for educational and professional use 30° / 60° / 90° DESIGN – Drafting triangle features holes up to 1/2" in diameter ALUMINUM CONSTRUCTION – Drafting triangles made from high-quality aluminum for long-term use without cracking or discoloration INCH AND CENTIMETER CALIBRATIONS – Aluminum metal drafting triangles are calibrated in both inches and centimeters for flexibility in professional drafting QUALITY IMPRINTING – Drafting triangles feature large numbers and holes which are printed using precise imprinting techniques that will not rub off with extended use and time