Unisex boot. 4mm CR Flex-Foam. CR Flex-Foam adjusts to the unique contours of your foot to create a comfortable and stable foundation while resisting blisters and chafing. PK mesh lining. Comfort topline. Reinforced toe and ankle. Rubber outsole with aggressive treat pattern. Upper: Rubber/Neoprene. Lining: PK Mesh. Sole: Rubber. Ref: UTFS4297