Product Highlights: battery-powered portable headphone amplifier. supported sample rates via USB input: up to 32-bit/384kHz PCM; 2.8MHz (DSD64) and 5.6MHz (DSD128). supported sample rates via optical digital input: up to 24-bit/192kHz PCM. Windows and Mac computers supported (free software downloads from Sony's website for playback). operating system requirements: Windows® Vista or later and Mac® OS X® 10.6.8 or later. ESS Sabre DAC (ES9018) 32-bit audio digital-to-analog converters with jitter reduction. high-bandwidth TI TPA6120 headphone amplifier for low noise and distortion. asynchronous USB data transfer for reduced timing jitter and better sound. gain select switch provides compatibility for a wide range of headphones and earphones. Digital Sound Enhancement Engine (DSEE HX) for improving compressed music sources. Three USB ports: micro type-B input for charging (cable included). micro type-B input for computer, Sony Walkman™, and Xperia™ smartphone or tablet connections (adapter cables included). standard type-A input for iPod/iPhone/iPad devices (these devices must use their own respective cables, not included). optical digital (Toslink) input. standard and balanced minijack (3.5mm) headphone outputs. combination minijack audio input/line-level output for connecting MP3 players, smartphones and other audio devices or driving an external amp or powered speakers. built-in lithium-ion rechargeable battery provides up to 5 hours of playback with a digital source using balanced outputs (up to 17 hours when connected to analog stereo input). durable rounded aluminum body with integral bumpers to protect volume control and headphone jack. recommended headphone impedance: 8-600 ohms distortion: less than 0.01% (1kHz) frequency range: 10-100,000 Hz (analog audio input) 3-1/8"W x 1-1/16"H x 5-1/2"D weight: 10.58 oz.