Which flint and steel firestarter is best?

I am looking for a flint and steel, not magnesium. There are just so many on the market that it is hard to know which one is best. I am looking for a flint that will last forever, not one that shaves away over time like some magnesium alloy ones will. Please share your experiences with me and, if possible, direct me to a website where I can buy one. Thank You!