According to Apple:
The “Magic Keyboard with Numeric Keypad features an extended layout, with document navigation controls for quick scrolling and full-size arrow keys for gaming. A scissor mechanism beneath each key allows for increased stability, while optimized key travel and a low profile provide a comfortable and precise typing experience. The numeric keypad is also great for spreadsheets and finance applications. And the built-in, rechargeable battery is incredibly long-lasting, powering your keyboard for about a month or more between charges.”
The keyboard used a Bluetooth connection and shipped with a Lightning cable for charging. It was 0.16–0.43 inches high, 16.48 inches wide, 4.52 inches deep, and weighed 0.86 pound.
This Space Gray color was discontinued some time in Summer 2021.
Source: Apple
