Before you decide to buy a HiFi (SBC/AAC/aptX/aptX HD/LDAC) Bluetooth headphones or speaker , you can verify your mobile first! The App is very easy to use , 1.Turn on mobile Bluetooth and connect/pair a device (ex.headset or speaker) 2.Click "Check Bluetooth A2DP" to list current using codec , local phone codecs and selectable codecs 3.Click to switch a codec