I bought one many years ago, it was called a "Permanent Match" (probably the brand name). I thought it was kind of junky because the fuel evaporated quite quickly; but in hindsight it probably wasn't a very good quality one.
Personally, I'd prefer to just carry a small ferrocerium rod on my keychain than one of these, but I'd want some good tinder to accompany it.
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"The mind is not a vessel to be filled but a fire to be kindled."
-Plutarch