Waygate Krautkramer B-320 [118-540-320] 4-Step Calibration Block Inch 1018 Steel. The Waygate Technologies Krautkramer 4-Step Block, a Baker Hughes business product (formerly GE Inspection Technologies), is for thickness and linearity calibration and made of 1018 steel. This 4-Step block comes in thicknesses of .250", .500", .750" and 1.000". Step face measures .750" x .750". NOTE: Variations of this block are available if additional steps are preferred. Also, larger step faces are offered for use with large diameter transducers. In accordance with ASTM E797.