5 mm neoprene provides comfort and flexibility along with excellent waterproofing shock absorption and heat retention properties adjusts to the shape of little feet to resist blisters and chafing Highgrade rubber exterior provides extra toughness and makes for a 100 waterproof kids boot Lightweight and breathable mesh lining keeps feet well ventilated for longwearing dryness comfort rated from subfreezing to 65 F18 C Selfcleaning diamond outsole Rubber toe and heel protectors extend the life of the boots