Teflon Coated Fabric Adjustable Brass Buckle Fastening Waterproof & Windproof One-Size Fits Most Inner Lining is 100% Polyester satin lining, with an inner trim band for extra comfort. Outer jacket (shell) is made from 60% wool, 25% polyester, 11% acrylic and 4% composed of other fibres, making this cap of top-quality fabric. Adjustable Velcro fitting with matching tweed lined band. Produced to the highest standards by a manufacturer of top-quality country wear and derby clothing. The tweed has been treated with Teflon, which acts as a fabric protector, making this product long lasting-lasting protection against oil- and water-based stains, dust and dry soil.