CES 2015: Kensington KeyFolio Thin X3 Plus for iPad Air 2 Combines Bluetooth Keyboard, Case, and Battery Charger The Kensington KeyFolio Thin X3 Plus for iPad Air 2 features an ultraslim Bluetooth keyboard case. Users can also charge iPhones and iPads via a USB port that connects to a 4,500 mAh battery. by James Geddes