It can be combined into a complete comfort grip, or taken apart as a wrist strap. You can shift to different control modes in different games.
Each grip is strategically shaped to make your Joy-con feel like a more traditional controller and be more comfortable when held in your hands during play.

LED indicator makes your player number visiable without taking out the Joy-Con.
Shoulder buttons of the grip allow full functionality of the SL and SR buttons at the top of the Joy-Con whilst.

The grip features a release button for easy detaching your Joy-Con.