SpencoŽ Performance Gel Heel Cups Heel Cups provide superior cushioning and direct energy where your heels need it most. Independent tests conducted by Sport Biomechanics, Inc. Anatomical Cushioning System- Dual density gel provides cushioning where the heel needs it most Heel Cupping- Provides extra cushioning and stability for the heel Performance TPR Gel- Thermoplastic Rubber combines superior cushioning and energy return for ultimate performance