It's not foldable, but it will fit in your pocket. This ultrathin, stainless steel, sleek Bluetooth 3.0 keyboard measures only 82mm x 206mm x 5.8mm or 8 x 2 3/4 x 3/16 inches. It comes in your choice of black or white keys. Unfortunately, it only supports IOS devices.
After a two hour charge, it will perform for up to a month, and the keyboard works up to 30 feet away from the device to which it's linked.
This keyboard features iPad hotkeys for convenience. But it does not come with a manual, so you have to figure it out on your own. There is a so-called manual you can download; it consists of one half page illustrating how to get connected with Bluetooth. Customer support is non-responsive.
The keyboard linked right up to both iPad and iPod without any difficulties, unlike some keyboards I've tested.
Rapoo, the manufacturer, sells many different Bluetooth, wireless keyboards in a variety of configurations. They also have a large selection of Bluetooth mice.
While its small size is certainly a plus for mobile computing, I found the keys a bit small for error free typing with my bear paws. Otherwise it's a quite handsome, functional unit that should make iPhone, iPod, and iPad users very happy to have an external, wireless keyboard for greater productivity. It's a shame it will not work on Androids and other digital devices.
You can bag one for yourself here at a cost of $55, which is very reasonable for a Bluetooth keyboard of this quality.