Features: Brand new and high quality Headphones speaker Amplifiers: Suitable for headphones and speaker, which can provide strong signal output and enhances sound quality experience. Stereo signal Amplifiers: As preamplifiers, it can increase the Volumes and dynamic of the input signal and improve the quality of sound. Double sound source with Volumes control: Two sound source can be connect, and users can easily switches and adjust the Volumes of different sound source through Volumes control. Transmission: Ensure sound quality, provide highly definition output, and there will be no distortions and quality degradation during transmission. Volumes control: With Volumes control function, users can adjust the Volumes of output sound according to their needs to meet individual needs. Specifications: Material:Metal Size:Approx.109x79mm/4.29x3.11inch Package Includes: 1Pc Signal Amplifiers note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you not mind before order. 2.Due to the differences between different monitors, the picture may not reflect the actual of the item.