Professional 16-600Ω Headphone Amplifier with Bass Boost, Portable HiFi Earphone Amplifiers, Gain Switch Bass Volume Adjust, Rechargeble Headphone Amp 3.5mm Jack for Phones, iPad, MP3, MP4

【With Bass and Volume Control Knob】With bass knob, you can flexibly adjust the intensity of the bass, providing a more delicate and mellow bass performance, giving you a more powerful music experience. Enhances the signal input to the amplifier circuit for optimal headphone performance.