This is a 3 pack of our Fresnel Lenses, which are made of optical pvc. They are 0.4 mm thick and weigh 5.5 grams. prices. We include the Fresnel Lens as standard equipment in several of our survival kits.MAGNIFICATION UP TO 4X - These lenses are great for reading small print, in low light, and viewing small objects.FIRE STARTER - These lenses double as fire starters. They are designed to ignite dry tinder and start a fire on a sunny day. They are a solid product for survivalist, campers, hikers, or anybody needing a last resort method of lighting a fire.COMPACT - They are thin, extremely light, flexible, and about the size of a credit card. They will fit in your wallet, purse, backpack, first aid kit, and go bag without weight or taking up space. Keep one handy in multiple locations for quick use.PROTECTIVE CASE - Each lens comes with its own protective sleeve.