Used from sea level to Mt. Whitney at 14000 plus feet. Magnesium is by far the hottest burning fire starting material you can purchase. Other fire starting materials burn from 700 to 1000 degrees. Our magnesium burns at 4000 degrees and will light wet tinder insuring you can have a fire even in wet conditions. Safe to carry and store in your backpack, BOB, survival kit or car. This is the best magnesium you can buy. It comes in compact lightweight zip lock bags. Please note that magnesium is a metal material that can oxidize when exposed to air or heat causing it to turn black, black magnesium will burn just as hot as silver colored non oxidized magnesium. We sell only pure magnesium with out any fillers. Remember you only have about 3 hours in extreme cold before hypothermia sets in. Our Magnesium guarantees you will have fire to keep warm. I have used magnesium for over 30 years and it has never failed to light a fire for me. Please use with caution. Any questions about how to light magnesium, please feel free to contact me. Steve Kaeser. See you on the trail. Thanks for looking