Endurance+ Fabric: Body made of 53% Polyester, 47% PBT. Drawstring waist for enhanced fit and security Front Liner made from Polyester. Classic sports styling, straight from the Speedo design archives. This sporty HyperBoom Jammer nods to our brand heritage with a revival of our iconic go-faster Boom Logo stripe. It's cut with a front support liner and an adjustable drawstring for comfort and security during training. Be ready to go again in the quick-drying Endurance+ fabric, designed for durability with high chlorine resistance. Body made of 53% Polyester, 47% PBT.