The bolt size and thread quantity regulations have common standards and public thread size, identifying the 6 to 3/4inch and 4mm to 16mm hardware. Each size has a nut and bolt checker in the same amount. There are 8 holes of the nut and bolt thread checkup, which are 4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 1/4 inches, 1/2 inches, which can help you quickly and accurately determine the screw size and recommend it. The drill or tap size required for the screw. Durable materials-bolts and nut recognition instruments are made of High-quality materials and 12.9-level hardness tools processed by CNC. The anode oxidation surface makes it stable and durable. The scale line is printed by the laser, and the easy -to -read tag belt has a bright black background. Public thread size- x 0.7-M5 x 0.8-M6 x 1.0-M7 x 1.0- x 1.0-M 8 x 1.25-M10-M10-M10-M10 x 1.5-M2 x 1.25-M2 x 1.75-M14 x 1.5-M14 x 2.0-16 mm x 2.0 British thread size-#6-32 fine-#8-32 fine-#10-24 thick-#10-32 fine -1/4-20 thick -1/4-28 thin-5/16-18 thick-5 /16-24 fine -3/8-16 thick -3/8-24 fine -7/16-14 thick -7/16-20 fine -1/2-13 thick -1/2-20 fine -5/5/ 8-11 thick 5/8-18 fine 3/4-10 thin Material: Metal colour: Black Package Contents: 1 x Bolt Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.