Meets all grade 24 AFBMA standards.
Chrome alloy steel, hardened to 63RC.
Surface finish to 1.5 micro-inches.
Within .0001"/0.0025mm of actual size.
Spherical accuracy within .000025"/0.0006mm.
Inches-includes: 26 pairs in English sizes 1/8" to 1"
Metric-includes: 25 pairs in Metric sizes 1mm to 25mm in 1mm increments.