Straight Edge is made of spring steel and is precision ground to rigid quality standards for Flatness and Parallelism. Edges are square (not beveled). Ideal for drawing or scribing lines and for checking surface straightness. This straight edge is nongraduated (no measurement markings). While the flatness and parallelism are precise, the dimensions are approximate. Approximate dimensions: 24 Inch Long x 1-13/32 Inch Wide x 5/16 Inch Thick. 0.0007" Edge Flatness, 0.0013" Parallelism. For over 60 years, SPI has introduced innovative products to the metalworking and laboratory industries. SPI measuring instruments are durable, precise and reliable — all backed by an Industry leading 2-Year warranty.