A USB wired keyboard that has Bluetooth. That seems like a contradiction, but it can be useful to the right user.
This is a nice keyboard, even without the extra Bluetooth feature. It has a good (high-quality) feel, which I prefer to the trend for "flat" keyboards that feel like laptop keyboards. It looks good. The keys "click" softly with a pleasant sound.
Here's a use that probably was not intended by its designers. I use it with my Mac that is connected to my HDTV in the living room. I have a regular power extension cord under the couch, to which I connected one of my spare Apple USB power adapters (from an iPhone). I connected this keyboard to that USB power adapter, to provide it with power for doing its Bluetooth thing. Instead of linking the keyboard to a mobile device, I linked it to the Mac, which is about eight feet away. A battery-powered Bluetooth keyboard I tried before was not reliable at that distance, but this Matias keyboard works nicely, perhaps because it is powered from an AC source. And I never been to replace batteries.
The keyboard has a small built-in "platform" to place an iPhone (or similar size device), between the main keys and the numeric keypad. I put my old iPhone there, running an app (Mobile Mouse Pro) that controls the Mac's onscreen cursor. It turns the iPhone's screen into a Magic Trackpad. Its location on the keyboard is perfect, as a little multi-touch trackpad.
NOTE: This platform on the keyboard only a place to put the device; there is no "docking" connection. It is made from rubber, and has an inward contour that is shaped for something with a curved casing (on the back side), like the iPhone 3G and 3GS. Other devices of similar size will "fit" there, but maybe not as precisely.
I had read reviews of the Matias keyboards in the past, but didn't see why I should pay all that money and replace my cheap keyboard. I was using a generic keyboard for my Mac. After seeing the sale on OWC, I purchased the One Keyboard. I must say, there is a difference! Not only are the keys like the "old school" keyboards, but the added feature of bluetooth switching allows me to use the same keyboard to type on my iPad. I now have my iPad, MBP, and external monitor on my desk, with one keyboard controlling it all.
This is one great keyboard. You can feel and hear the keys as they are depressed . This Keyboard also allows you to integrate your iPhone, iPod Touch or iPad with the Bluetooth capabilities of the Keyboard and then use the keyboard with that unit. Its by far the best Keyboard I have owned since the early 90's.