The LTM5 AIRFLO® Tilley Hat is designed with a medium brim and ¾" polyester mesh in the crown for coolness and comfort during hot days and strenuous activities. Made with Tilley Nylamtium®, a strong water-and-mildew resistant form of lightweight nylon.Features:Guaranteed for lifeInsured against lossExcellent sun protectionRepels rainSecret pocketTies on in the windMachine washable ( WON'T SHRINK)Material:Nylamtium®.The fabrics of all Tilley Hats have been certified to block 98% of harmful UVA/UVB radiation and deliver an ultraviolet factor (UPF) of 50+, the maximum rating is given.Brim Measurements (size 7 3/8):- Front: 2 5/8"- Back: 2 3/4"- Sides: 2 1/8"Size Assistance:54.5 cm = 6 7/855.5 cm = 756.5 cms = 7 1/8 - Average women's size57.5 cms = 7 1/458.5 cms = 7 3/8 - Average men's size59.5 cms = 7 1/260.5 cms = 7 5/861.5 cms = 7 3/462.5 cms = 7 7/863.5 cms = 864.5 cms = 8 +Tilley's care advice:Wash it frequently or non-removable sweat stains will mar it and possibly rot it. Machine wash on delicate cycle separately or hand wash in cool water. Do not use bleach as it remains inside the Hat, slowly rotting it. Smooth and reshape the Hat by hand and set it out to air dry. When the Hat is dry, simply re-stretch it, as an American sailor showed, by putting your knee in the crown, and pulling firmly on the opposite side. Tilley LTM5 Airflow Hat | Natural