With standard Lotus socket external sound input, it can be connected to computer, mobile phone, and other audio devices. You can select full frequency or low frequency output; there is no human voice output in low frequency mode. Features short circuit protection and reverse connection protection for added safety. The built-in squelch circuit helps eliminate noise, resulting in clearer and more pleasant sound quality. Color: as shown Material: PC + metal Package Contents: 1 x Car Power Amplifier Board (Note: Due to different batches, the appearance of the product may vary, but the function remains the same) Packaging includes only the items listed above; other accessories are not included. Note: Lighting and display differences may cause slight variations in color. Measurement error allowed is +/- 1-3 cm.