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.