Do you really need another USB adapter? Well the NOMAD devices (are they devices?) are really easy to carry around with you all the time, so you never have to be without a USB adapter.
The Card is just that, a credit card sized adapter with two bits that push out, one being the normal USB bit that plugs into a laptop or charger and the other bit is a micro-USB plug or Lightning plug. It's a bit thicker than a normal credit card, but not much and it will fit in a wallet credit card slot, Oysters holder, or jacket without much fuss.
The Clip is about the same length as a key and has a "loop" at the micro-USB/Lightning end. It does look a bit like a key when viewed at the right angle. This easily fits on a key ring and won't look out of place.
Both products are pretty durable, though if either was REALLY bent a lot, the plastic could become stressed, though it would require a LOT of effort.
Though they can both be ordered off the NOMAD site, they're now available on Amazon.
That sounds quite a lot for what's basically a USB cable, but it's not much for being able to carry something around all the time, so being able to charge your phone or tablet wherever you are (ok you might not have a charger, but it's often easy to find a USB port somewhere, the issue being never having the right cable with you). The NOMAD solutions just fit the bill - well your wallet or key holder.