To get going, simply remove the burner, fill the warmer with the included cup, replace the burner, and hold a lit match or lighter to the exposed filaments. Once the flame catches, put the metal cover over the burner and surround the entire device in the fire-resistant warming bag. Hot enough to feel through insulated clothing, safe enough to avoid any concern, and almost odorless for hunters and sports fans alike, Zippo hand warmers are the best way to beat the cold in the fight for your fingers.