Alvin 748PM metric drafting scale ruler. This professional quality, 30 cm metric draftsman scale is made from high-impact plastic with white, non-reflecting dull-matte faces, and tapered edges. Machine-engraved graduations and color-coded furrows. Supplied in storage case. Graduations: (1:20, 1:2.5, 1:33 1/3, 1:50, 1:75, 1:100). Alvin 748PM metric mechanical draftsman scales are made in Germany.