Product Description 4-Step Block for thickness and linearity calibration (Aluminum or Steel) Step thickness: .250″, .500″, .750″ and 1.000″. Step face: 750″ x .750″. In accordance with ASTM E797. Dimensions: 3.00″ x .75″ x .250″/.500″/.750″/1.000″. Please specify Aluminum or Steel in comments field at checkout
