Practical machine accessories: This 23 hole clamping block is suitable for adjusting, layouting and testing various machine tools, parallel horns for milling machines. Robust and durable: The parallel blocks are a hexahedron, made of hardened steel, ground and hardened on all sides, ideal for work for precision assembly. High precision: This high-precision parallel milling block has an accuracy of up to 0.0001 inches. Height accuracy precision adapted blocks. The unique design makes your work smooth and provides excellent performance. 23 hole design: This terminal block has 23 holes, including (5) 3/8-16 threaded holes for clamping and (18) unopened holes. These steel blocks can be used for setup, layout and inspection work. Suitable for all types of machine tools. Use scenarios: - Setup and clamp workpieces on milling machines to ensure proper alignment and repeatable positioning. - Perform layout and inspection tasks by using the block as a reference for measurements and markings. - Build fixtures or jigs for precision assembly and testing, leveraging the 23-hole pattern and threaded holes for multiple clamps.