Best Glide ASE Credit Card Size Fresnel Lens Fire Starter and Magnifier Lenses (3 Pack - Green)
These make a great back-up fire starter for sunny days. Carry one in your wallet and use it to conserve matches or firesteel. With a little technique you can use this to ignite your tinder bundle. Be sure to practice this skill before ending up in a situation where you need to rely on it!