These convenient disposable heaters give off heat on demand. Tear outer plastic wrapping remove, shake gently and you instantly have heat to put where you need. They are safe, no flames, fuel, cords or batteries. The mini hand size, 2 1/2" x 3", lasts for 7 to 10 hours. The New Toe Heaters have a brand new added feature: ADHESIVE BACKING. This allows the Toe Heaters to stay exactly where you put them. Simply stick the Toe Heater to the outside for your sock, slip your foot into your boot or shoe, and enjoy FIVE LONG HOURS of nice, warm feet. No mess, no odor, just clean dry heat! Both Heaters sold in pairs only.