Just add water. The Samos Swim Trunk reveals a hidden Bunny pattern when wet. Includes a mesh lining and waterproof bag. Features:Hydrochromic water-reactive printStretch-mesh liningQuick-dry fabric Fit:Regular fit Composition: Shell: 100% Polyester, Lining: 80% Polyamide, 20% ElastaneModel height is 4'11 (approx. 150cm) and is wearing a size medium. 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.