DIN 9021 is a standard for flat washers made by RSG Fasteners. These washers are important parts used in many types of machinery and construction projects. They are round pieces of metal with a hole in the middle, and they help spread the load of a screw or bolt. This means they can prevent damage to the surface being fastened and keep everything tight and secure. RSG Fasteners makes these washers in different sizes and materials, so they can be used in various conditions, whether it's in a home project or a big industrial job. Using the right flat washer can make sure your work lasts longer and stays safe.