How does it work? Inserts are made of a special fabric which holds the cooling energy for an extended period of time. Water causes a naturally cooling effect as it evaporates. Simply submerse in water for 1 to 3 minutes, or until garment reaches the desired level of hydration.  Gently wring out excess water and it's ready to wear! No freezers or cold packs necessary.  Once activated, the insert will provide many hours of cooling relief in low-humidity climates. Bucket Hat with Evaporative Insert (#BH) features: One (1) evaporative cooling insert Hook and loop tabs attach easily to the hat. One (1) cotton bucket hat Unisex Wide brim protects your face from the sun! Color: Blue Size: One size fits most Polar Products Evaporative Bucket Hat