Socket to loosen/tighten top cap on Mountain Bike RST Mozo Pro forks. Helps avoid gouging when using tools that don't have a snug fit on the cap bezel. Designed to use a 22mm socket or 3/8" socket handle. May fit other RST models but haven't researched this. Print hex side down - will result in support artifacts on the flat surface but I prefer it flat and also means that socket internals will be printed smooth.