Kela Bear Large Size Body Warmer with Adhesive,up to 10-14 Hours Do not directly contact with the skin. Simply open the outer package and expose the packet to air. Grabber warmers are pre-mixed so no shaking is necessary Adhesive backing keeps warmer firmly in place, Up to 10-14 hours of warmth KeLa Bear warmers are a non-toxic, odorless heat sources using all natural ingredients that are non-combustible.Air-activated instant heat source,Portable (No wires or batteries), odorless, disposable, safe Production Date29 October 2014 . Valid : 3 years.