These two channel gauges, are made of hardened stainless steel and have two grooves with a graded slope (dependent on the model chosen).
Graduated in microns, mils, NS (Hegman) or PCU (North), the gauges have an accuracy of ±3μm (0.12mil) or ±5% whichever is the greater. The groove width for all models is 12mm (0.47”) with a groove length of 127mm (5.0”).