He created a bracelet that eliminates the pressure around the wrist and turns a functional hair tie into a stylish accessory by creating a channel that holds the elastic hair band in place. (honeywerehome.com)
In other words, you don't need a separate set of 5 hair bands for each kid. (happyyouhappyfamily.com)
Find an elastic hair band or if you don't have one, just measure around your child's head and cut a piece of elastic that length. (vixenmade.com)