Chill-Its 6716 Cooling Hard Hat Liner - Polymers, 13.25 x 1.88, Blue Polymer cooling technology quickly activates for up to four hours of relief from the heat. Hook and loop closures securely attach to forehead of suspension and fits most hard hats and safety helmets. No-bulk wear under hard hats. 100% cotton. Simply re-wet to reactivate cooling. Hand wash and hang in open air until completely dry.