#8 U -Style Clip-On Nut, U-Type Fasteners

Benefits of U-Nuts
You don’t need any special tools or equipment to install U-nuts. They are simple fasteners that are easy to install. To install a U-nut, you just need to clip it onto the edge of a sheet metal panel. You can then drive a screw through the central hole to hold those panels together.    

There are different options from which you can choose when shopping for U-nuts. If you want to use a particular screw size, for instance, you can choose U-nuts that support your preferred screw size. Some U-nuts are designed for use with M4 screws, whereas others are designed for use with 6Z or 8A screws.
You aren’t limited to using U-nuts in any single size. They are available in different sizes. When shopping for U-nuts, you should consider the length and width, which represents their overall dimensional size. And you should consider the U-nuts’ hole size. Check both the diameter of the hole and the distance from the center of the hole to the edge of the U-nuts.