Alvin Clear-Angle drafting triangles are made of heavy-duty, 0.125" thick acrylic plastic, with die-engraved graduations and a white protractor arc. Double row of graduations on the protractor arc shows complementary angle at any setting. Angles from 0 to 90 degrees in 1/2 degree increments. Built-in magnifier allows exact settings. Available in 4 sizes. Alvin adjustable plastic drawing triangles are made in Germany.