There's a lot of products out there that can do two very different things at the same time. The one that captures the imagination the most is the Swiss produced Rinspeed sQuba, a fully submersible convertible. There hasn't been any action on them since the prototype came out in 2008, but we're still waiting with bated breath.
On the more mundane side of things, there are times when you've got to bring cash and card with you in one simple device. The Leather Money Clip Wallet does exactly that, merging a durable spring money clip with a classy billfold in a way that looks good and slips into a pocket without hassle. With 4 card slots, a back pocket that works great with contactless cards, and an internal spring money clip, this wallet does double duty while looking good. Just like the sQuba, you can take it from daytime on the beach to nighttime in the big city without a change.