The giant robot slippers make sounds such as “vrrrrrr”, “clank”, and so on, and if you so desire you may turn the sounds off using an on/off switch. These are one-size fits most adult humans. The interior space for your foot is 8 inches wide and 13 inches long. the giant robot slippers with sound fit up to a U.S. Men’s size 12 (Ladies’ 14), but they might even fit a bit bigger. How they work, the leg is made to hug your calf, so even if your foot is much smaller than a men’s size 12, they should hang on.