This ultra-slim iPad Air 2 Keyboard Cover by Anker is the same size and has the same thickness as the iPad Air 2. The rechargeable lithium battery has a 6-month battery life between charges. Your iPad turns on and off automatically with the opening and closing of the keyboard. Available at Amazon.com.
iPad Keyboard Cover by Logitech
Logitech Keyboard for iPad 2 and New iPad 3 is an ultrathin aluminum-matched protective cover and stand for the iPad.
The iPad keyboard uses the same magnets as the Apple Smart Cover and accessories. Once it’s attached to your iPad, it looks like an Apple netbook.