Metric Hex Metal Self Locking Nuts. Material: A2 304 Stainless Steel. Sizes: M3, M4, M5, M6, M8, M10, M12, M14, M16, M18, M20. Packing: Plastic bag / Carton box. For specific parameters, pls refer to picture 2. According to your Choose! We care about our valued buyers, if you have any questions, our Customer Service staffs will be very glad to help you. We try our best to reply to your emails as soon as possible, however, due to high volume of daily incoming emails and time zone difference, we may not be able to reply your emails immediately. About item:For the functional products in our shop, we make sure that the functions are the same as description, but the actual color and shape may looks a little different from pictures because of the technical improvement and manufacturing variance.