I didn’t even know that such a product existed, but how handy!
I have a bike taillight that charges by USB, and both iPad and iPhone can be charged by USB as well. As well as a host of other peripherals, like LED reading lights.
According to OWC, it is the only UL Certified product of its type on the market, for both USA and Canada.
Beware of other non-certified products which might put your safety at risk.
Replace your standard outlets with the NewerTech Power2U Wall Outlet and you get dual USB charging ports right on the outlet. Very cool.