Apple Magic Wireless Keyboard 2 - MLA22LL/A Silver A1644 sale
It pairs automatically with your Mac; the battery is incredibly long-lasting - it will power your keyboard for about a month or more between charges
Connections and Expansion: Bluetooth, Lightning port & Wireless
Height: 0.16-0.43 inch (0.41-1.09 cm); Width: 10.98 inches (27.9 cm); Depth: 4.52 inches (11.49 cm)