Grade 0 precision gauge block: Meets national metrology standards for lab and high-accuracy calibration. Made of high-speed steel: Offers superior hardness and wear resistance for long-term industrial use. Wide length range: Covers common sizes (e.g., 1.005mm to 50mm) for versatile measurement tasks. Mirror-finished surface: Excellent flatness and smoothness ensure stable contact during measurement. for caliper and micrometer calibration: Widely used in inspection, tool verification, and machining setups.