Acoustic Research AR-M20 Hi-Res compatible audio player(Japan domestic model) Built-in memory: 32GB / external devices: micro SDXC Slot (up to 200GB) USB connection: micro-B (charging, data transfer, USB-OTG device connection) / Output: only headphone output (3.5mm standard stereo mini plug) / output voltage: 2.1Vrms unbalanced connection / Output S / N: 114dB / headphone output: 16: 228 + 228mW / 32: 130 + 130mW / 300: 15 + 15mW Supported OS of PC connection: Windows 7 or higher / Mac OS X 10.6 or higher Body size: Width: 70mm  height: 136mm  Depth: 10mm / weight: 177g Accessories: USB cable (micro-B), LCD protective film, carrying pouch