Magnesium block with ferro rod strip firestarter works in the harshest of conditions. This Firestarter even works when it is wet. It's waterproof and fire resistant in block form.
All you do is shave a little pile of magnesium onto your tinder and scrape the ferro strip so that the Sparks land on the magnesium pile.
This style of firestarter is best suited for bug-out and go bags.
The shavings burn at 5400° F