Speedo Women's Compression Swim Short Outer : 100% Micro Polyester. Internal : 80% Nylon / 20% Extra Life Lycra. Imported Solid swim short with wide elastic waistband features a built-in compression short with 20% LYCRA XTRA LIFE fiber Speedo's Compression Technology: Provides a more efficient workout, Speeds up recovery time, Increases support, Slims the body & Optimizes calorie burning Built with our exclusive VaporPLUS fabric that repels water and dries in record time Outershell Fabric: 100% Micro Polyester