Incredibly small and light, the USA-made Exotac NanoStriker can get a fire going anywhere and anytime you need one. Its waterproof ferrocerium and magnesium rod is user-replaceable and good for more than 3,000 strikes from the sharp tungsten carbide striking tool. When not in use, the rod is held safely inside the anodized aluminum body while the striking tool serves as a cap complete with hole for attaching to a keyring or lanyard.
Length: 3.65" (closed), 4.17" (extended) / Diameter: 0.43" / Ferro Rod Diameter: 0.25" / Weight: 0.95 oz.
As seen in Uncrate Issue 04.