The TYR Durafast Polyester Diamondback Swimsuit with Striping is built with 100% polyester, Durafast(TM) is 100% chlorine proof for 72 hours of exposure. This durable fabric lasts 20 times longer than traditional swimwear. Durafast(TM) provides 100% colorfastness in addition to unsurpassed sun resistance. The TYR 4-Way Stretch Technology helps Durafast(TM) swimwear maintain its excellent fit.