S-Boston Pocket Hand Warmer, Patented Technology, Black x1 + Red x1, Self Ignition, No Naked Flame, Up to 20 Hours Heat

I finally received these handwarmers and they are great. They are somewhat delicate so they will need to be handled with the respect they deserve as they do run off of flammable Lighter Fluid. They do not burn with naked flames as you would expect. The magic is the Platinum Catalyst inside the top cap, which makes the fuel fumes undergo catalytic conversion releasing steady yet very hot heat as well as some combustion fumes in the process. So significantly reduced risk of fire.I picked this hand warmer specifically because it can be ignited via 2 AAA batteries with a small resistive wire inside. You can also easily shut off the hand warmer by opening the top cap and rotating it to cap off the fuel tank to the platinum catalyst. Very convenient compared to the more traditional Zippo Handwarmer, though I cannot comment much on those as these are my first pair.Not only are they effective as hand warmers, they really warm your thighs very well in the cold. They come with leather pouches to insert them in for easier handling when they inevitably get too hot to handle.They are also supplied with an easy to fill fluid bottle with measurements in cubic metres. If you only the bottles half-way on your first go. Only refill half way again to prevent overfilling the tank if you have not finished the first run. Doing so could contaminate the delicate platinum catalyst.I've heard about the battery covers coming loose and eventually breaking from other reviewers. But I try to be very gentle when opening and closing it. So a tip, if the battery cover refuses to shut with batteries in, do not force it. Rotate the batteries and try again, or the batteries you are using may be a little too big. Try another pair. But as a safety net, I was supplied with spares, so that's great.All in all, I recommend for the cold weather Heathens.