Shure SHA900 Portable Listening Amplifier with USB DAC and Customizable EQ Control 4-band Parametric EQ features five preset settings and four customizable settings to maximize audio playback fidelity Enhanced Audio Control provides additional user-friendly options to maximize audio playback fidelity Streamlined controls for quick and simple navigation throughout the SHA900 settings Multiple output gain structures optimized for both headphones and earphones. Headphone impedance range: 6 to 600 ohms Integrated USB rechargeable battery can conveniently charge from provided wall charger or computer, even when streaming USB audio from computer Compatible with Mac, PC, iOS and Android devices via included accessory assortment, featuring Micro-B to Lightning and Micro-B OTG cables Premium Shure fit and finish and construction featuring an elegantly machined aluminum housing, manufactured to exacting Shure quality standards