Feature: 1. Multi Specifications: This kit includes 44 pieces thread gauges, 23 imperial and 21 metric specifications, for nut and bolt thread inspection and identification. 2. For Narrow Spaces: These thread checkers have compact structure, can be used to measure threads in narrow or enclosed spaces, convenient and practical. 3. Carbon Steel: These thread size identifiers are made of excellent carbon steel, with high hardness, wear resistance, impact resistance, and has a long service life. 4. With Storage Box: This kit includes a sorting box with clear nut and bolt labels, black for metric and silver for imperial, for convenient and quick identification and use. 5. Wide Applications: These thread checkers have standard sizes to ensure accurate identification, suitable for plumbers, repairmen, automotive mechanics, etc. Specification: Item Type: Nut Bolt Thread Checker Material: Carbon Steel Included Specification: Metric: M3x0.5, M4x0.7, M5x0.8, M6x1.0, M7x1.0, M8x1.0, M8x1.25, M10x1.0, M10x1.25, M10x1.5, M12x1.25, M12x1.5, M12x1.75, M14x1.5, M14x2.0, M16x1.5, M16x2.0, M20x1.5, M20x2.5, M24x2.0, M24x3.0 Imperial: 6-32, 6-40, 8-32, 10-24, 10-32, 1/4-20, 1/4-28, 5/16-18, 5/16-24, 3/8-16, 3/8-24, 7/16-14, 7/16-20, 1/2-13, 1/2-20, 9/16-12, 9/16-18, 5/8-11, 5/8-18, 3/4-10, 3/4-16, 1-8, 1-12. Package List: 44 x Nut Bolt Thread Checker 1 x Storage Box