The cotton-top wraps the little feet just like comfy socks - easy to put on and take off. Superior elasticity helps keep them on. Non-toxic, BPA free, ultra-light (32g - size 5), recyclable, 100% TPE (thermoplastic elastomer) rubber material (often used in baby teething toys) keeps it both soft and supportive - making it easier to walk and run. Tiny holes on the sole for air circulation. Beehive patterned TPE natural rubber sole is perfect for indoor and outdoor.