No matter how tough the competition, a swimsuit made with Nike NX is even tougher. Harsh, chlorinated water is hard on swimwear fabric, so Nike Swim Competitive Team designers set out to create a chlorine-resistant nylon fabric that could withstand long seasons of training and competitive team racing. The result is NIKE NX for swim team competitions: an incredibly durable, colorfast fabric that retains its shape through the life of the garment. Rigorous testing included the equivalent of 500 hours in colorfast testing in everything from pool water to sea water.