Muck Boots MB Derwent II Boot Quality, functionality and comfort in one product. These mid-height boots are perfect for muddy wet conditions. The upper is reinforced in both the toe and ankle area, plus a rubber outsole with aggressive tread pattern helps grip. Fastening:Slip On Material Composition:Other Materials/Other Materials/Other MaterialsCare Instructions:N/A 4mm CR Flex-foam. PK Mesh Lining. Comfort topline. Reinforced toe and ankle. Rubber outsole with aggressive tread pattern. Temp rating 0C to 18C. CR Flex-Foam adjusts to the unique contours of your foot to create a comfortable and stable foundation while resisting blisters and chafing.