This scale is designed to measure from reduced scale drawings, such as blueprints and floor plans, but also works as a handy all-purpose ruler. Designed with engineers in mind, this scale is fully divided with gradations of 10, 20, 30, 40, 50 and 60 decimal parts to the inch.Details:12" (30.48 cm)12 engineering scalesFeatures easy-to-read gradationsColored grooves make it easy to identify scaleDurable plastic construction