Casual flat. i flex soles are made of Thermo Plastic Rubber, an indoor outdoor material that is waterproof as well as non marking. This innovative material enables the shoe to bend up to 90 degrees. In addition, the outsole provides a non slip surface that is both soft and durable delivering the perfect marriage of fashion, fit and function. Leather or manmade upper; mouse over your color choice for upper information. Man-made lining and sole.