Apple Smart Keyboard (for iPad Pro 12.9) Price: $78.59 (as of 02/06/2019 08:12 PST- Details)

It’s a full‑size keyboard that’s fully portable, and connects to iPad Pro with the Smart Connector, an innovative new interface that allows for a two‑way exchange of power and data.
Just attach the Smart Keyboard and start typing.
When you’re done it folds together to create a slim, lightweight cover.