The X stands for Xtreme in this modern reboot of PUMA's 1980s Running System sneaker that pushes the limits of proportion, texture, shape and even comfort. Deconstructed and rebuilt with an even bolder mix of materials and colors, it takes inspiration from the puzzles and games we play in our extra time. Style Name: Puma Rs-X3 Puzzle Sneaker (Women). Style Number: 5892128. Available in stores.