High Accuracy Carbide Gauge Block Made from tungsten carbide for exceptional hardness, wear resistance, and long-term dimensional stability in precision measurement. Grade-Level Precision for Calibration Manufactured to ISO 3650 standards, suitable for calibrating meters, calipers, and other high-accuracy instruments. Mirror-Lapped Surface Finish Each block features a mirror-polished surface for superior wringing performance and minimal deviation. Corrosion-Resistant Carbide material resists corrosion and deformation, for demanding industrial environments and metrology labs. Protective Wooden Box Packaging Comes in a sturdy wooden case for safe storage, organization, and transport of gauge blocks.