I too found them at the local Target, under the Thermos brand name.  Appears to be mostly parafin.  Lit one and noticed that the flame peaks a bit at first, then subsides to a moderate flame for a few minutes, then slowly tails off.  It left quite a residue on the stone, including the remnants of the wrapper.  Still, I think it suitable as a good tinder source for firemaking.  Good find.
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The ultimate result of shielding men from the effects of folly is to fill the world with fools.
-- Herbert Spencer, English Philosopher (1820-1903)