Charging cables that are at your fingertips all the time just keep getting smaller and smaller. Back in March of this year, TUAW reviewed the ChargeCard, a USB to 30-pin Dock Connector charging cable the exact size of a credit card. Now there's the ChargeKey for iPhone 5 (US$25), an even smaller emergency charging cable that's the size of a house key.
Not surprisingly, both products are made by the same California company, Nomad. The design of the ChargeKey makes it a snap to attach to your keychain or to remove it for a quick charge. On one end is an open-faced USB connector, while a Lightning connector sits on the opposite end. If you're anywhere that there's an open USB port, you can plug in your iPhone (or iPad -- the ChargeKey is designed to withstand up to 3.1 A of current) to top it off.
At $25, you're really paying for the convenience of having a cable you can attach to a keychain. Apple's Lightning to USB cables run $29, but other manufacturers sell short 4-inch cables for as low as $11.90 each.
The company is doing an initial production run of 10,000 ChargeKeys, and plans to ship them to purchasers on November 30, 2013.