Made of TYR's most durable and flexible textile possible. Durafast Elite. the RDUS7A utilizes high denier poly fiber and innovative circular knit construction. to combine the strength and colorfastness of polyester with the comfort of spandex. Offering minimized coverage and a compressive fit for reduced drag. the Durafast Elite Brief is able to sustain 300 hours of use while maintaining a comfortable hold on your body and is 100% chlorine proof.