I made this simple tool to be able to remove these after-market rocker box covers, and adjust the valves, without having to take the gas tank or carbs off. Sure, I could have just bought a 30mm wrench, but I had this 30mm socket lying around that I had to modify (destroy) to work on a BMW back in the day anyhow. This simple tool is also much lighter than its store-bought counterpart, so would be better to carry in a tool roll too. And there is enough left of the socket to make two or three more, if need be, since this one will go with the bike to its new owner. When finished, I also zinc-plated it for durability.