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. 44 x Nut Bolt Thread Checker1 x Storage Box Item Type: Nut Bolt Thread CheckerMaterial: Carbon SteelIncluded Specification: Metric: M3x 0.5, M4x 0.7, M5x 0.8, M6x 1.0, M7x 1.0, M8x 1.0, M8x 1.25, M10x 1.0, M10x 1.25, M10x 1.5, M12x 1.25, M12x 1.5, M12x 1.75, M14x 1.5, M14x 2.0, M16x 1.5, M16x 2.0, M20x 1.5, M20x 2.5, M24x 2.0, M24x 3.0Imperial: 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 Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.