Syba SD-DAC63093 Portable Headphones Amplifier with 3 levels of Bass Boost Specifications: Maximum 5X Headphone Power Output Gain Two Headphone Outputs Allow for Sharing Music on the Road Compatible with Apple and Samsung In-line Control Headphones Two levels of Bass Boosting S/N Ratio:> 90 dB (A-Weighting) Maximum Headphone Output Power: ~250mW / 16ohm Headphone Drive Ability: 16 - 150ohm Built-in Rechargeable Battery Life Time: 8 hours Ports: Analog Output: 3.5mm Stereo Headphone Jack x2 Analog Input: 3.5mm Stereo Headphone Jack x1 Charging Input: Micro USB x1 Switches: Bass Boos Selection: Switch x1 Power Switch and Volume Control x1 LED: Power on, Battery Charging and Battery Low indication includes: 1x Bass Boosting Dual Output Headphones Amplifier 1x User Manual 1x 3.5mm 4-pole to 3.5mm 4-pole Cable (11) 1x Micro USB Cable (38)