The world's only vertical swimming aid, the Swimfin Swim Float works for the youngest children who are taking to the water for the first time, to the seasoned swimmer who wants to improve stroke technique. SwimFin has been tried and tested and is proven to work for all ages, sizes and abilities. However, the packaging there is a chart saying SwimFin is suitable for children 15-30 kgs and gives an approximate age range of 3 - 6 years. Worn on the back, it gives the arms and body complete freedom of movement. Brightly coloured so easy to spot in the pool. How to wear Swimfin. Wear high on the back, above the centre of gravity. This way it will suspend the child in the water. SwimFin will not tip a child forward if worn correctly. Should never be used with a baby that cannot control their body yet. SwimFin must NEVER be worn on the front of the body. To be used under constant, capable supervision.