I have compared 4 brands of magnesium bar with attached ferrocerium rod firestarters both to their efficacy and durability. The video shows all the details... but my final recommendations are:
Doan Magnesium Firestarter Tool (http://amzn.to/1Ms7J25)
and/or
The Friendly Swede Magnesium Fire Starters (3 Pack) (http://amzn.to/1FUqOVY)
This video is featured in this blog article: http://ecoculturevillage.org/survivalways/the-magnesium-bar-with-attached-ferrocerium-rod-firestarter-comparison/
Enjoy the out of doors and stay warm, my fellow Steemians!