Gauge blocks (also known as gage blocks, Johansson gauges, slip gauges, or Jo blocks) are a system for producing precision lengths. The individual gauge block is a metal or ceramic block that has been precision ground and lapped to a specific thickness.

• Grade 0 gage blocks supplied with a certificate of inspection that the blocks meet American Society of Mechanical Engineers (ASME) B89.1.9
• High-carbon, high-chrome steel provides high hardness and wear-resistance
• Rectangular shape for accurate wringing
• Nominal length (in inches) indicated with laser-etched, black characters
• Identification number etched in block for traceability