what is a smart connector

From iPad Pro - Smart Keyboard - Apple

“The Smart Connector transfers both data and power between iPad Pro and the Smart Keyboard — no batteries or charging required. Just attach the keyboard and start typing. When you remove it, the onscreen keyboard automatically reappears.”

It's the three circles on the edge of the iPad Pro, that connect to the smart keyboard. It's a built in part of the iPad Pro models.

It is not available on the 9.7" 6th Generation iPad if that affects your decision any.

You're welcome. Glad I have helped.