Our GROOVE set of 4 hair + wristbands is amazingly bold and bright with retro colors and patterns to get you feeling groovy as a bracelet while holding your hair up in style. Medium is the size of a normal hair tie band. It fits wrists between 5-6.4" around. Small is better for younger girls and small teens.  It fits wrists under 5" around. Large is sized for wrists 6.5-7.5"