Back Float , Petforu 4-Layer Swimming Kickboards Learning & Training Safety Belt Back Floatation Device for Kids /Swimming Beginner L SIZE: 31x23x8cm /12.20x9.06x3.15in. CONVENIENT: Super strength nylon strap. The back belt is adjustable. PRACTICAL: Easily buckles on your back, freeing arms for proper motion. A GREAT TOOL to help kids learn swimming, also ideal for swimming beginner. GREAT TEACHING TOOL: Easy to snap on and adjust. Easy for the kids to swim in. Same as their swim class ones.