The Aquastar Fabric Swim Vest was designed with soft, smooth fabric to prevent irritation to the skin, while have a UPF of 50+ to keep kids safe from the sun's ray. Built in foam pads allow toddlers more confidence while learning to swim. The adjustable buck and zipper allows one to adjust the vest to the perfect size. The small/medium size is perfect for kids ages 1-3, 24-40lbs.