The Iron Key is a metallic USB flash drive that is "built to withstand attacks both virtual and physical." On the virtual front, the data is protected by a secure password. After 10 incorrect password attempts, the encryption chip will automatically self-destruct, rendering all the contents completely unusable.
On the physical front, I'd imagine that this drive can suffer a fair bit of abuse too. They mention that the innards contain all sorts of epoxy. This way, if someone tries to physically pry the thing apart to get at the chips, "he'd more likely damage them instead."