The SPI 0.05 to 4" Bore Gage Block Kit Calibration Master delivers exceptional precision with accuracy to 0.00005". This comprehensive calibration master is designed for professionals who require absolute precision in dimensional measurement applications. The kit includes a range of blocks that allow for accurate calibration of bore gages across a wide measurement range from 0.05" to 4". Manufactured by MSC Industrial under the trusted SPI brand, this calibration master is an essential tool for quality control departments, metrology labs, and precision manufacturing facilities. The durable construction ensures long-term reliability, while the precise tolerances help maintain measurement accuracy across your inspection tools. This calibration master helps ensure consistency in your measurements and compliance with quality standards, making it an invaluable addition to any precision measurement toolkit.