【Digital to Analog Audio Converter】 This DAC converter can convert optical, coaxial and Bluetooth transmitted digital audio signals into 3.5 mm audio signal output. Addresses an issue when connecting different audio interfaces to an analog amplifier. 【Music Player with USB Flash Drive】It is also a digital music player with USB flash drive input that supports MP3, WAV, APE, FLAC and WMA lossless formats. You can always play music files stored on a USB flash drive and output to speakers via optical 3.5mm for better sound quality. 【Widely used】Digital to analog audio converter is suitable for home theater, teaching, training structure, conference room, electrical appliance store and other places.