Precision craftsmanship: Our Gauge Block set is made of grade alloy steel, ensuring durability and reliability. Each block is carefully hardened and ground to deliver exceptional accuracy in your measurements. Versatile design: Each parallel features two holes for easy and secure mounting, enabling reliable use across metalworking and precision engineering tasks. These blocks help maintain parallelism and achieve precise measurements. Extensive size range: The set includes 9 pairs of 1/4' thin matched pairs in various sizes, ranging from 1/8x1/2x6 to 1/8x15/8x6. With this comprehensive selection, you will have the right gauge block at hand to meet the demands of any project. Unrivaled accuracy: Designed with a parallelism tolerance of / .0002 in height, the set provides consistent and accurate results. Trust in the craftsmanship and quality control to ensure you get precise measurements every time. Practical applications: Use for establishing parallelism in fixture and vise setups for milling or drilling; verifying height references and flatness in surface plate metrology; setting up precision jigs, fixtures, and machine setups in metalworking or quality control tasks.