85%Nylon/15% Spandex * Promotes natural and proper balance in the water with non-removable strategically placed foam inserts * Helps non swimmers learn to swim and be better prepared for structured swim lessons * Promotes the development of muscles, coordination, endurance and confidence * Sizes: Extra Small: 20 to 30 lbs, Small: 30 to 40 lbs, Medium: 40 to 50 lbs, Large: 50 to 70 lbs