Precision meets durability with SPI's 9/16" diameter Chrome Steel Gage Ball. Engineered to exacting standards, this calibration tool features an impressive 0.0001 inch tolerance and Grade 25 accuracy, making it ideal for the most demanding measurement applications. The 63 RC hardness rating ensures exceptional wear resistance and dimensional stability over time. AFBMA certification guarantees this gage ball meets industry standards for quality and performance. Perfect for calibration, layout work, and machine setup tasks, this chrome steel ball maintains its dimensional integrity even under regular use. The polished chrome finish provides smooth surface characteristics essential for precise measurement applications. Whether you're working in quality control, tool calibration, or precision manufacturing, this SPI gage ball delivers the reliability and accuracy professionals demand.