Both stylish and practical, these swim vests act as a transitional flotation aid that lets your child build water confidence while staying safe. Made of UPF 50 neoprene, they're built for a snug, comfortable fit all day, whether worn over a rashguard or not. Where our Floaties keep buoyancy near the arms, these center it around your child's core so the arms stay free for a full range of motion. Kids get a stable float while relying on their own movements to get around. They are not a life jacket, nor are they rated for use on a boat. This swim aid is meant to help your children build confidence and grasp swimming fundamentals while remaining safe in the water. We recommend a child be somewhat at ease in the water beforehand, and the vest must be used under parental supervision. Small: 1-3Y (22lbs - 40lbs) - 22" Circumference | 12.5" length Medium: 3-6Y (40lbs - 66lbs) - 24" Circumference | 14.5" length We suggest buying for your child's age to get the right length and fit. Recommended for children with some water comfort, they also include: crotch strap for fit and safety removable inner flotation so you can add or take away based on your child's comfort and experience neck loop for easy hanging and grabbing of little ones sized vests for a better fit by weight.