For thickness and linearity calibration.
The 5-Step block Inch version has step thicknesses of .100", .200", .300", .400" and .500".
The 5-Step block Metric A version has step thicknesses of 2.5, 5.0, 7.5, 10.0 and 12.5 mm
The 5-Step block Metric B version has step thicknesses of 2.0, 4.0, 6.0, 8.0 and 10.0mm
Step face measures .750" x .750". In accordance with ASTM E797.
Dimensions: 3.75" x .75"
Fitted wooden storage case optional