From Team Fortress Wiki
The Valve quality is assigned to items that are given to Valve employees. In some cases, they have the Flying bits particle effect attached. Because of their nature as developer items, they may possess stacked attributes as seen in the backpack example, however, these additional attributes are not part of the Valve quality itself. The Valve item shown in the backpack example is Robin Walker's Rocket Launcher.The hexadecimal color code for Valve items is .
Flying bits attached to the Escape Plan