As a musician you know you need to practice regularly to hone your skills and learn new songs. However; you can't always break out the amps and crank up the volume. For those times when quiet is required; you can both practice and hear the amplified output from your instrument using this Rechargeable Mini Headphone Amplifier for Guitar from Monoprice!This amplifier is designed to provide amplification to the output of instrument level devices; such as electric guitars and bass guitars. It features a 1/4 inch TS plug; which plugs directly into your instrument's output. It is powered by an internal; rechargeable battery and has a 3.5mm TRS output for listening with headphones.An additional 3.5mm TRS auxiliary input is provided for connecting another audio source; such as an mp3 player. The audio from the Aux jack is mixed with the audio from the guitar so you can play along to an existing recording.This amplifier produces a Tube Overdrive inch sound with distortion and delay reminiscent of Classic Rock performances. The amplifier includes analog Gain; Tone; and Volume controls.Note: The distortion effect that this amplifier produces means that there will necessarily be some background hiss/noise; even at normal volume levels. If you listen to the amplifier without it being plugged into a guitar; the noise level can be loud and pronounced. However; when it is plugged into a guitar the signal returns to a desirable noise level for playing.