Swim trunks that come alive in the water. With sun soaker style and a splash of just-add-water personality to make sure you're the talk of the pool party. Waterproof bag in back pocket.Woven - 100% Polyester mechanical stretch, inside net 76% polyamide, 24% elastaneMade in ChinaRegular fitHydrochromicSilicone Bunny patchDrawstring at elasticized waistQuick-dry fabric Hydrochromic is a term used to describe a type of material that changes color when exposed to water. In the context of swim trunks, hydrochromic materials are used to create a unique and dynamic look. When the trunks come into contact with water, the material changes color, revealing a hidden design or pattern. The color change is temporary and returns to its original state once the fabric dries.