Achieve precision measurements with the SPI Rectangle Steel Gage Block (0.128"), Grade AS-1. This high-quality dimensional measurement tool comes complete with NIST Certification, ensuring accuracy and reliability for your most demanding calibration needs. Manufactured by MSC Industrial under the trusted SPI brand, this rectangular steel gage block (Part #15-042-5) is designed for professional use in calibration, layout, and machine setup applications. The durable steel construction provides consistent measurements and long-lasting performance. Perfect for quality control departments, machine shops, and precision manufacturing environments where exact measurements are critical. This gage block serves as an essential reference standard for verifying measuring instruments and establishing dimensional accuracy in your workflow.