Grade 0 precision gauge block: Complies with ISO 3650 for high-accuracy measurement and instrument calibration. Standard 25 mm length: for verifying calipers, micrometers, and other precision tools. Premium hardened steel construction: Provides excellent wear resistance and long-term durability. Mirror-finished surface: Ensures smooth contact and stable, repeatable measurements. for inspection and lab use: Widely used in metrology calibration, machining, and quality control., Manufacturer: CFWWSAQ