Description:100% brand new and high qualityFeatures:Aux in jack allows you to play along with MP3/phone player. A true analog circuit faithfully simulates the response of the original amplifiers. Classic rock produces a great high-gain sound. Plug and play. Specification:Type: Headphone AmplifierMobile/MP3 Input Jack: 3.5mmHeadphone Input Jack: 3.5mm Connector Diameter: 6.35mm Power Supply: 2x AAA Batteries (Not Included)Material: PlasticColor: BlackSize: App. 3.7x8.7x2.2cm/1.45x3.42x0.86inQuantity: 1pc Note:Transition: 1cm=10mm=0.39inNot retail package. Please allow 1-2cm error due to manual measurement. Pls make sure you don't mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package Included: 1 x Headphone Amplifier (Other accessories demo in the picture are not included.)