The Pony2.O is the same diameter as the Pony-O, but is a slimmer piece. The sleek 2.O is designed for sections of hair and will make any half-up hairstyle pop! You can also use the 2.O for a smaller stand on the ponytail (less perky) or if you have super fine hair. It's great for fine-haired children too! Designed to last hundreds of uses.