Key-shaped USB flash drives have guaranteed we never forget to bring our important files ever again. Taking the same approach, Bluelounge's Kii guarantees you always have an emergency iPhone or iPad charger on hand -- as long as you remembered to lock your home and bring your keys.
A 30-pin dock connector version of the Kii, available in black only, is the cheaper of the two at just $20. But if you have the latest generation iPhone or iPad, you'll need to cough up twice that amount -- $40 -- for the black or white Lightning version.
We're assuming you're helping to cover Apple licensing fees for the new connector, but even at $40 it's still worth every cent if it means you're not scrambling to borrow someone else's Lightning cable or dimming your device's display to near unusable levels just to max out its dwindling battery.