1, 5.0 bluetooth version, transmission efficiency is higher, transmission distance is .2. size heat sink ensures efficient heat dissipation.3, potentiometer to adjust the volume, with a switch, easy to control the volume, suitable f DIY speakers.If it is a metal box, you need to draw out the bluetooth antenna. 4. Copper DC connect is adopted to withst high current no heat.5. 4470uF green gold capacit guarantees the power stage capacity the continuous stable power supply is the premise of good sound quality. 6. The DC head with cable can be compatible with the input power interface of this product. Even if you 't have the DC head adapter battery, you can connect it . Adaption Supply Voltage: 5-24V (9V or 12V or 15V or 18V or 24V adapter, recommended high voltage) Power Supply Voltage: 12V- - - 8hom speaker or 24W (Left channel) and 24W (Right channel), 4 ohm speaker or 40W and 40W,15V- - - 8homs or 32W and 32W, 4 ohm or 60W and 60W,19V- - - 8homs or 64W and 64W, 4 ohm or 80W and 80W,24V- - - 8homs or 72W and 72W, 4 ohm or 100W and 100W Parameter: Product Name:HIFI with filter 2X100W Bluetooth digital power amplifier board Model: -1002L Chip Solution: domestic With Without Filter: Yes Adapter Speaker: 50W-300W, 4 ohm-8 ohm Number of Channels: Left right stereo (Stereo) Bluetooth Version: 5.0 Bluetooth Transmission Distance: 15m(Without occlusion) Protection Mechanism: Overheating protection,Sht Circuit protection colour:black Material:Metal andpc Package Contents: 1 Bluetooth 5.0 Digital Amplifier Board 1 shell 1 screwdriver 1 power cd Notes f use: the power switch on the board is stby switch, the machine is in stby state with low power consumption after the switch is turned off. Tocompletely turn off the power to remove the DC plug on the machine f a long time, it is ok. Tip: To have enough output power if the audio input is sufficient the supply voltage or current is sufficient. The power supply voltage is higher the relative power will be larger. The speakers with different impedances will have different output power. In the case of sufficient voltage current, the larger the ohms of the hn, the smaller the relative sound power. pay attention Only the above package content, other products are not included. Note: Light different displays may cause the col of the item in the picture a little different from the real thing. The measurement allowed err is 1-3cm.