QUINT Premium Professional Inking Triangles are manufactured from .320cm extra heavy premium smoked acrylic that will not discolour or warp with age and handling. They are machine cut with double inking edges for inking without smearing, and are hand polished for maximum accuracy. The smoke tint provides enhanced visibility on the drawing surface. They feature a convenient cutout centre for quick and easy lifting from any angle. Packaged in a heavy duty protective poly bag. Made in the USA.