Specifications: Size: 7 different sizes: M3 (50Pcs) M4 (40Pcs) M5 (30Pcs) M6 (20Pcs) M8 (10Pcs) M10 (5Pcs) ) M12 (5Pcs) Material: 304 Stainless Steel Color: Sliver Quantity: 160 pcs Feature : The hex nuts with caps design can isolate the screws from outside air, and also can prevent water or other corrosive substances from entering, so that the service life of the screw can be longer. And the hex head nuts can fit the wrench well during the nut removal process. There are total 7 different sizes of lock nut that you can choose for different bolts and use them in various situations. They can prevent vibration from loosening a bolted joint, resist loosening under vibration and torque to provide a locking action. Suitable for mechanical equipment, electronic equipment, communication equipment, hardware lighting, etc. Pay attention: The color of the actual items may vary slightly from the listing images due to different computer screens, thanks for your understanding. Due to manual