Feature: 1. Mode Switching: The input mode switch button can be used for USB, storage card mode and memory card radio, easily switching between "mode" and "line in mode". 2. Wireless Connection: Press enter to switch to USB or storage card indicator HT or turn on your phone's Bluetooth, find Bluetooth "LDZS" and click to connect. 3. Card Mode: Insert a USB flash drive or storage card, and the amplifier can play automatically. The "Previous Song", "Next Song" and "Pause Playback" buttons are for easy control. 4. Radio Mode: Press input to switch to radio mode, then press the play button, the amplifier will automatically search and save the channel. 5. Perfect Configured: Support EQ sound effect, can switch a variety of sound effects, 20HZ‑20KHZ frequency response, MP3 and Bluetooth format, can be controlled by remote control. Specification: Item Type: Car AmplifierMaterial: Aluminium alloy .Input Voltage: 12V Output Power: 20W x 4 Frequency Response: 20HZ-20KHZ Harmonic Distortion: 1KHZ 0.055% 4W High Pitch Control: 10KHZ± 12db 220mv 47K Power On Control: 100HZ± 12db 220mv 47K Card Reader: Storage Card/USBFormat: MP3, Bluetooth Remote Control Battery: 1 x CR1220 (not included) Package List: 1 x Car Amplifier1 x Manual1 x Remote Control