As cool as these are we need to REMEMBER they're Lithiun-Ion batteries and should be used with extreme caution especially while re-charging them. They're somewhat susceptible to spontaneously combust too so that's another consideration.
I LOVE the concept and glowing (no pun intended) reports of their usefulness but still more than a bit skeptical of their long term "health".
Good thing I'm almost over-stocked on Element fire extinguishers.