Exofficio Women's Bugs Away Chas'r Short Sleeve Tee Fabric is a blend of 60% cotton, 35% polyester and 5% Lycra elastane and is moisture and wrinkle resistant. Insect Shield is made from an EPA-registered, odorless insect repellent called permethrin that is made from the chrysanthemum plant. Shirt is machine washable and the Insect Shield treatment is good for 70 washings. Moisture-wicking Dri-Balance fabric keeps you dry and comfortable during outdoor activities. Built in Insect Shield Repellent treatment fends off bugs and insects.