With AUX and Bluetooth two audio input methods, 2-in-1. 5.0 Bluetooth version, the transmission efficiency is higher, the transmission distance is farther. Bluetooth audio amplifier module 2.1 channel, Max output power 2X50W+100W. With antenna and antenna base, the signal is better, the efficiency is high, and the anti-interference ability is strong. With short-circuit protection as well as overcurrent, overheating, and anti reverse connection protection to prevent total failure. In the event of an overload, the device reports the fault condition to the processor to protect itself from damage. It adopts copper DC connector and fence type terminal. It can withstand large current, no heat, no damage to the wire. With bass, treble, subwoofer frequency and volume control, easy to adjust volume, enjoy the music tone what you want. Widely used in store solicitation, home theater, square speakers, etc. This model is an upgraded version and supports "Wuzhi Audio" APP control. Wuzhi Audio APP download link for Android phones: http: //.qingdaowuzhi.cn/appdownload/Wuzhi_Audio.apk For iOS phones, please search "wuzhi audio" in the to download and install it. Model: -MT21 Bluetooth Version: 5.0 (without occlusion 15m) Audio Input: AUX + Bluetooth Output power: left and right channels Less than50W; Subwoofer Less than100W Channel: 2.1 Input sensitivity: 500mV Adaption Supply Voltage: DC12-24V / 5A above (Do not connect to 24V battery pack) Speaker: 20-100W, 4-8Ohm Output Power: max 50W @R&L channel; max 100W @subwoofer Protection Mechanism: anti reverse connection, overheating, overcurrent, short circuit protection Attention: The product can be connected to an external antenna, but does not include the antenna and antenna base. Please purchase separately. Material: PCB+electronic components+metal colour: Black Package Contents: 1 amplifier module 1 x Enclosure kit with mounting accessories 1 x Adapter 1 x screwdriver (The needs to be assembled by yourself, the screwdriver color is random, Cannot be chosen the specific color.) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.