Productive Product: No, that's not a misspelling: Energizer markets its lithium (not li-ion) backup system for portable gadgets with the "Energi To Go " moniker. Basically this is a battery holder fitting one or two AA cells, a power charging and management chip from Techtium , and your connector of choice. The AA cells cost about $10 for four (or $5 for two, but good luck finding two-packs in most stores), with the full setup giving you a bit more than one full device charge for a high-end smartphone or MP3 player. Energizer sent me a two-cell version and, as advertised, it promptly charged my Treo 700p. I do see a couple of design flaws: it's very difficult to read the battery polarity markings inside the holder, the battery covers comes off too easily, and Energizer says it's not necessarily good for overnight full recharges because some devices can "wake up" when a connector is attached, thereby draining more power than they'll obtain. And, I wonder, why not have device manufacturers use such retail-oriented batteries (in rechargeable versions) in the first place? Philips is almost there , giving some of their phones an Energizer lithium cell but only for backup purposes. Regardless, this is a nice $20 option if you go on a trip and forget to take your wall charger, and you can buy different tips at Batteries.com  rather than buying a second Energi To Go for additional devices.