About this item COOL DOWN TO DO MORE - On the field, on a bike ride, or at the job site, this helmet liner keeps you comfortable, even under bulky helmets of all kinds. Made with breathable fabric, it cools you down instantly when activated with water or sweat. PERFORMANCE FEATURES - This lightweight helmet liner provides UPF 50 sun protection and is designed with a mesh crown for enhanced breathability. It’s ultra-compact and can fit in your back pocket—perfect for job sites or on the go. THE COOLEST TECHNOLOGY - HydroActive Wet-to-Cool Technology cools fabric up to 30 degrees below average body temperature in under 1 minute & stays cool for up to 2 hours. Activate & reactivate in 3 steps: wet it or sweat, wring it out & wave it. WASHABLE & ODOR FREE - This helmet liner is machine washable and resists unwanted odors for lasting freshness. The proprietary cooling technology will never wash out of the fabric. UNISEX - The universal fit design is made for both men and women and provides all-day comfort