Alvin 241BP black engineer's scale ruler. Pro-quality, triangular engineering scales are made from high-impact plastic with black, non-reflecting dull-matte faces, and tapered edges. Machine-engraved, white graduations and color-coded furrows. Graduated in 10, 20, 30, 40, 50, and 60 parts to the inch. Includes storage case. Quality-made in Germany.