On Cloud X Women's Running Shoe Welcome to zero gravity — engineering for those on a mission. The Cloud X is the result of what happens when you take the sole of the Cloud and remix it for athletes who don’t define themselves by any one sport, or any one type of workout. Soft landings. Explosive take-offs. A knit-weave on top and a speedheel cap to keep your heel on lock. Make no mistake, this is the lightest, fully cushioned running shoe the world, your gym, and your feet have ever seen. All you have to do is get out and mix it up.