EcoFlows Power Hat allows you to power all your adventures thanks to solar charging on the go. 360-degree solar panels enable solar energy to be captured from all angles without any blind spots. Built in Dual USB-A and USB-C ports give users the ability to charge two devices simultaneously. At only 13.1 oz, the Power Hat is lightweight and easy to pack. Thanks to material that is IP65 waterproof and dust proof rated, the Power Hat is ideal for hiking, beach trips, fishing, and outdoor activities. Adjustable Velcro in this Medium-Large option ranges for head sizes 22.4 inches to 22.8 inches in diameter.