The Anita Care Pure Fresh Swim Bilateral Breast Form (1086X) is specifically designed for activity, including swimming. This single breast form is thermal, chlorine and salt water resistant. The grooved underside allows for air circulation and water drainage. Made from 100% Silicone. If you prefer a breast form without a grooved underside , check out the Anita Care Pure Fresh Shell Swim Bilateral Breast Form (1047X), sold separately.