Tilley TM10 Mesh Hat weighs only about 5 ounces! * GUARANTEED FOR LIFE * INSURED AGAINST LOSS * EXCELLENT SUN PROTECTION * REPELS RAIN * TIES ON IN THE WIND * MACHINE WASHABLE (WON`T SHRINK) Tilley Mesh Hats are lightweight, cool and comfortable because the crowns are made of strong ‘3-D’ polyester mesh which blocks sunlight, but allows air to pass easily. The mesh has also been treated to provide water repellency. The 100% cotton duck brims block sunlight. Tilley Mesh Hats have been tested and certified as having a UPF 50+, the maximum UV protection rating given. The TM10 Mesh Hat is styled with the broader brim size of the Tilley T4 model. Brim Measurements: Front and Back: 3 1/2" Sides: 2 1/2" If you give us your head’s measurement (inches or centimetres) on the Sizing Guide on the website, we’ll give you the right size. Or refer to our Hat Sizing Chart for the easy reference to your Tilley Hat size.