Silipos WonderSpur Heel Cups Molded, soft, biochemical-grade WonderZorb silicone. Won't dry or bottom out. Hypoallergenic, nontoxic, non-flammable, odorless, and washable. Use in dress or athletic shoes. Heel cushions do not get warmer than body temperature. Sizing: X-Large - Women's 12 , Men's 11