From its delicate ribbon detail to colorful embossed snake print or basic black leather options, this flat's a true ballet beauty. Available in women's whole and half sizes 5, 6-10, 11. Fits medium (B) widths. Callisto Flats Vio-Motion Technology is designed to hug your arches and support your feet in comfort. Vionic flats built-in orthotic is shown to be effective in helping to treat heel pain (plantar fasciitis). These fashion shoes will be your new casual basic ballet flat favorites! For the greatest comfort, we recommend wearing your new Vionic footwear for just a few hours for the first few days to allow your feet to adjust to the new level of orthotic comfort and support. Within one to two weeks you should find the product completely comfortable and supportive. There’s a science to our style Vionic shoes provide essential stability and addictive support. With contours seamlessly engineered into each and every pair–from flip flops to heels–Vionic helps support natural alignment from the ground up, in looks you’re going to love.from the ground up, in looks you’re going to love.