Use this OTG cable to connect an Android phone or tablet to a control board. With the EZ-Gui Ground Station app you can have full control over Baseflight / Cleanflight / Betaflight settings. This cable plugs into the phone and enables communication. You'll also need a standard Micro USB cable to plug into the control board.
Invaluable for tuning at the field and making changes when you don't want to bring a laptop.