Grubs Childs Muddies Icicle 5.0 Boots Charcoal. Keep your little ones toes warm and dry with the Muddies Icicle 5.0 Boots from Grubs. Perfect for kids with a keen sense of adventure, the Muddies Icicle 5.0 are a calf length boot with a kick rim for easy, hands free removal â€\\\" perfect for uninterrupted playtime. With a hard wearing, quality rubber outsole for perfect grip, the Muddies Icicle 5.0 are designed with 5mm of Insufoam-Ultraâ ¢ neoprene for ultimate comfort and warmth with ankle high rubber for excellent waterproofing abilities. With an underfoot chassisâ ¢ for foot stability, the Muddies Icicle 5.0 allows for a comfort rating from -20 ºC to +20 ºC.