Up to 8 hours of warmth while you're having fun outdoors with Yaktrax Hand Warmers 40 count. Using real ingredients including iron powder, water, salt, activated charcoal and vermiculite, these air-activated hand warmers create odorless heat to keep the frost at bay. Perfect for running, camping, fishing, skiing and more - make the most of your outdoor pursuits and snuggle up with natural heat wherever you roam.