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, 20HZ20KHZ frequency response, MP3 and Bluetooth format, can be controlled by remote control.Item Type: Car AmplifierMaterial: Aluminium alloy Input Voltage: 12VOutput Power: 20W x 4Frequency Response: 20HZ-20KHZHarmonic Distortion: 1KHZ 0.055% 4WHigh Pitch Control: 10KHZ 12db 220mv 47KPower On Control: 100HZ 12db 220mv 47KCard Reader: Storage Card/USBFormat: MP3, BluetoothRemote Control Battery: 1 x CR1220 (not included)Package List1 x Car Amplifier1 x Manual1 x Remote Control