Here's what other sites are saying:
The waterproof REI Cascade Sombrero is perfect for boys who like to play in damp climates when the weather turns sour. Laminated nylon with sealed seams is waterproof, yet allows moisture vapor from perspiration to escape. Soft inner headband and mesh lining wick moisture away to help keep heads dry. Adjustable chin strap keeps the hat secure in windy weather.