From Gramicci: - Lightweight cap - Made with Active Shell material - Polyester 100% - Water resistant - Adjustable sizing for a perfect fit The Gramicci Shell Jet Cap is made of Active Shell material, a water-resistant material that is suitable not just for town but also for water play in the lake or ocean. Apart from being water-repellent, it also blocks wind, making it a good general-use material suitable for outerwear that can handle sudden rain or wind during transitions between seasons. The fact that there is a webbing belt in the back to adjust the size is a detail that is exclusive to Gramicci. This outdoor cap is suited for the outdoors and the city.