Precision Inspection Gage Ball Set - Metric Features include... 25 Pairs in Metric sizes from 1mm to 25mm 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm 8mm, 9mm, 10mm, 11mm, 12mm, 13mm 14mm, 15mm, 16mm, 17mm, 18mm, 19mm Chrome Alloy Steel, hardened to 63 RC Surface Finish to 1.5 u inches Within 0.0025mm of actual size Spherical Accuracy within 0.0006mm
