Features: Brand new and high quality Material: This inch and metric thread detectors are made of high hardness metal, which is durable and practical. Used For: It is used to easily and accurately identify nut and bolts by thread. Design : One end of each size has a male gauges, and the other end has a female gauges. Two Sizes: Silver inch size with inch size marking, including 23 common sizes. Black indicates metric sizes, with metric size marker and 21 commonly used sizes. Convenience: All strung together, with hangings rings, very convenient. Specifications: Inch Sizes: 6-32, 6-40, 8-32, 10-24, 10-32, 1/4-20, 1/8-28, 5/16-18, 5/8-24, 3/8 -16, 3/18-24, 7/16-14, 7/18-20, 7/2-13, 1/2-20, 9/16-12, 9/18-18, 9/8-11 , 5/4-18, 3/4-10, 3/16-16, 1-8, 1-12 Metric sizes: M3-0.5, M4-0.7, M5-0-8, M6-1.0, M7-1.2, M8-1.25, M10-1.1, M10-2.0, M10-0.25, M10-1.5, M12-1.4, M12 -2.5, M12-1.75, M14-1.3, M14.2.0 and M16-1.6, M16-2.2, M20-1-5, M20.2, 2.5 and M24-3.0 Material: Metal Color: silver and black Overall length: Approx.128cm/50.39inch Note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1 Set Thread Checker