1Multi Specifications: This kit includes 44 pieces thread gauges, 23 imperial and 21 metric specifications, for nut and bolt thread inspection and identification. 2For Narrow Spaces: These thread checkers have compact structure, can be used to measure threads in narrow or enclosed spaces, convenient and practical. 3Carbon Steel: These thread size identifiers are made of excellent carbon steel, with high hardness, wear resistance, impact resistance, and has a long service life. 4With 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. 5Wide Applications: These thread checkers have standard sizes to ensure accurate identification, suitable for plumbers, repairmen, automotive mechanics, etc. 44 x Nut Bolt Thread Checker 1 x Storage Box 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. Sold by-Minnanxin