This part is the replacement air filter for your small engine, used for outdoor power equipment. It has a black plastic rim that is approximately 2.5 inches by 2.5 inches. The air filter in your small engine prevents dirt and debris from entering the cylinder, where it can cause more serious damage. If your air filter is clogged, it can decrease your engine performance, and it will need to be cleaned or replaced. If the filter is damaged, it will need to be replaced as well. This is an OEM part sourced directly from the manufacturer, and is it sold individually.