The Shimano Women’s SH-TR501 Triathlon Shoe Integrated seamless midsole and upper construction set a new level of fit stability and lightweight performance Low stack height midsole stabilizes foot and maximizes power transfer efficiency T1-Quick strap and extra-wide collar simplifies foot entry and quickens transitions Quickly secure shoe during transitions with easy to grab asymmetrical heel loop 3D breathable mesh improves airflow and dries quicker Women’s specific last for a natural comfortable fit Lightweight glass fiber reinforced nylon sole for power transfer Adaptable Cup Insole