HHIP 50 Piece 1-25mm Precision Steel Gage Ball Set A 50 Piece (25 pair) precision steel gage ball set is commonly used for measuring, inspection, calibration, and gaging applications. Manufactured to tight tolerances (0.00012"/0.003mm) for precise measurements. Made from hardened chrome steel for durability and wear resistance. Hardened to 60HRC. Ground and lapped. Used for measuring hole diameters, calibrating micrometers, inspecting part tolerances, and checking bore dimensions. Commonly used in machinist setups, quality control, and precision measurement labs. Balls are manufactured with a high degree of roundness (Grade 24) to ensure consistency. Comes in a well-organized case with labeled compartments for easy size identification and access.