The keys are actually quite chunky, I would have preferred a card which I could have just shoved in my wallet and forgotten about until I needed it.
They're about 5cm by 1½cm and 3-4mm thick, with a hole in one end, so presumably you can put them on a keyring or similar.
I had a flash drive which seemed to be of a similar sort of construction on my key ring, and dropped my keys which resulted in bits of flash driving going everywhere. I hope thiese keys are a bit more rugged.
I wonder if they are thin enough to shove somewhere into my wallet, in a pocket or part of it that doesn't get used otherwise?
I've gone online and activated them, so now all I need is some bicycles in the stands!
The envelope also had a nice little pamphlet in it, which is a map of London with the docking stations on one side, and has things like instructions, charges, do's and don'ts on the other side.