- Size: 40 • Waterproof boots for kids: made with durable, flexible, and waterproof natural rubber. The handcrafted vulcanization process reduces weak points in the rubber, ensuring your children's health with 100% BPA-free and non-toxic materials. • Fun guaranteed: made of soft and flexible rubber with a durable non-slip profile, allowing kids to run and jump with confidence. Tested to withstand over 100 hours of activity without broken seams or leaks. • Safety function: non-slip sole with deep grooves that provide strong traction and drain water, improving traction on smooth surfaces. The sole is self-cleaning, preventing the buildup of mud and dirt. • Keep feet dry and comfortable all day: leak-proof design made from a single piece of highly elastic natural rubber, keeping your children's feet completely dry. Sweat-absorbing cotton lining that allows feet to breathe. • Soft and comfortable lining: polyester and cotton blend lining that provides comfort and absorbs moisture, preventing chafing and discomfort.