The HPG519 BTL App is designed to pair with the HPG519 BTL boombox speaker,a combination LED light and Bluetooth speaker.The HPG519 BTL App gives the user full control over the Music Play,Light change,equalizer,USB/SD card play ,FM control and Line In play.It provides the ability to control and adjust the volume,brightness,flash light modes of your HPG519 BTL boombox speaker as same as the remote control.