For $26, the kit upgrades your GameCube pad so it can be used with the 8BitDo GC Retro Receiver, giving you a Bluetooth connection for wireless play.
Because it uses a Bluetooth connection, you'll also be able to use the modified pad to play games on Switch and Android.
It comes with a 300mAh battery which offers around six hours of use between charges. You charge it via the included USB-C port.
The 8BitDo Mod Kit for Original NGC Controller is expected to ship on September 25th.