battery is dying- doesn't last long - can be resolved using a power bank. bt receiver/bt transmitter/ usb dac 3.5mm Up to 2TB microSD | Native DSD Support | Supports PO/LO/Spdif FiiO M5 AK4377 32bit /384kHz DAC chip Hi-Res Bluetooth Touch Screen MP3 Music Player with aptX/aptX HD/LDAC, USB Audio/DAC,Supports Calls