Niigata Seiki SK Japanese-made Steel Pin Gauge, Single AA Type, Total Length 50mm, AA 24.96mm

This is the most popular type for checking the accuracy of hole diameters, etc.

Nominal dimensions are printed on the pin gauge for sizes 1,000 mm and larger.

Country of Origin: Japan Diameter Accuracy (μm): ±2 Circularity (μm): 1.6 Diameter Variation (μm): 1.6 Hardness (HV): 650 or higher