Easy to Use - All models feature a double-taper cutout center for quick, easy lifting from any angle, making each project more efficient. Durable Construction - Made with extra-heavy acrylic that won't warp with age and handling for long-lasting use. Clear Drawing - Refracted light has an illuminating effect on the drawing by accentuating the triangles edge. Multi-Purpose Tool - Designed to be versatile for many projects, including those invloving architecture, engineering, and drafting. Great for students, hobbyists, and professionals alike. Precision Design - Designed for accurate and reliable measurements and consistently straight edges to make every project consistent.