The Tinder Hot Box has no moving parts, no flint, fuel or gasses! The air/water tight case means you will always have dry tinder to start your fire. The inside bottom of the tinder box is a parabolic reflector that focuses all solar energy to a singular point just below the base of the removable and stowable tinder holder arm. Works great with wild tinder such as dryleaves and easily ignites charcloth. The top of the Tinder Hot Box is also a signal mirror. Dimensions:2.625" in diameter, .725" thick. Weighs: 4 oz.