The hand warmer is not designed to be airtight. The fumes of the lighter fluid, mixed with oxygen in the surrounding air, power the reaction that generates the heat. Over time, the fluid will evaporate. That means you can’t just fire up a catalytic hand warmer days or weeks after you fill it—you’ll have to take the time to fill the unit every time you want to use it.
Zippo’s hand warmer is our consistent favorite among catalytic models. It continues to offer excellent performance, and may still be the best option for some people. But the best choice for most people, as we see it, can also turn on and off, charge a phone, work cleanly and odor-free, and still provide plenty of heat.
Buck Gardner relies on Heatmax products to keep him warm when he's hunting.
"Heatmax products are great on those cold mornings when we're hunting duck or geese. The Neck Warmer with the HotHands warmers inside is great to keep my neck and ears warm and the Hand Warming Muff with the HotHands inside keep my hands warm and limber for using my calls and shooting. "It keeps my calls from freezing up when it is really cold"! I never go hunting without HotHands!"
Product: makes reusable hand warmers that generate heat with a supersaturated solution of sodium acetate. The result: a heart-shaped packet that gets warm very quickly and can be reset hundreds of times. Just drop the activated warmer into boiling water to return the solution to a liquid.
Catalytic hand warmers generate heat by a reaction between a catalyst (in this case a platinum filament in the replaceable burner) and the fumes from lighter fluid. Catalytic hand warmers are built similarly to a common cigarette lighter. There’s a reservoir filled with batting, which you add lighter fluid to, topped by a replaceable burner, which contains a catalyst. Apply a flame to the burner to start the reaction, and then your hand warmer will continue to generate heat until the all of the fuel is depleted.