This premium 600mm straight edge is meticulously ground and lapped for straightness and parallelism, and they feature a beveled edge with a precision mm scale, which means they double as precision rulers. They feature a hanging hole and include a protective case if you prefer to store them in a drawer. Technical Details: iGAGING Precision Straight Edges are made of hardened steel. Accuracy: 0.001". Thickness: 3/16". Width: 1-9/16". Satin Chrome finish. All edges have true right angles. Bevel edge has a mm precision scale.