MBT Bititi Black Calf Leather Women's Shoe Features include: Calf leather upper Microfiber lining Side zipper for easy on and off Removable insoles so that you can add your own orthotic insoles Dual density midsole is made with TPU and nylon mixed with glass fibers for extra firmness and durability Multi-layered sole creates natural instability to emulate the feeling of walking on sand Casual rubber outsole provides good shock absorption and traction The MBT Bititi has a calf size of 15." Be sure to measure the width of your calf first.