Women's Aerosoles Casta Pumps Packed with comfort technologies, Casta, by Aerosoles, features modern lines and fluid, architectural details. It starts with a molded unit outsole that is flexible, featuring our proprietary diamond flex outsole. Then, we leverage our new proprietary Aerofly insole – a special foam molded to be half-firm for heel stability, and half-soft for rebound comfort. This is your new core pump for work, which delivers outstanding, all-season performance. Modern looks with all-day, all-night comfort and support.