1, 5.0 bluetooth version, transmission efficiency is higher, transmission distance is longer.2. Large size heat sink ensures efficient heat dissipation.3, potentiometer to adjust the volume, with a switch, easy to control the volume, very suitable for DIY speakers.If it is a metal box, you need to draw out the bluetooth antenna. 4. Copper DC connector is adopted to withstand high current and no heat.5. 4*470uF green gold capacitor guarantees the power storage capacity and the continuous and 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 don't have the DC head adapter or battery, you can connect it easily. Adaption Supply Voltage: 5-24V (9V/12V/15V/18V/24V adapter, high power recommended high voltage) Power Supply Voltage: 12V------8hom speaker/24W (Left channel) + 24W (Right channel), 4 ohm speaker/40W + 40W,15V------8homs /32W + 32W, 4 ohm/greater than 60W + 60W,19V------8homs /64W + 64W, 4 ohm/greater than 80W + 80W,24V------8homs /72W + 72W, 4 ohm/greater than 100W + 100W Parameter: Product Name:HIFI with filter 2X100W Bluetooth digital power amplifier board Model: ZK-1002L Chip Solution: domestic With or Without Filter: Yes Adapter Speaker: 50W-300W, 4 ohm-8 ohm Number of Channels: Left and right stereo (Stereo) Bluetooth Version: 5.0 Bluetooth Transmission Distance: 15m(Without occlusion) Protection Mechanism: Overheating protection,Short Circuit protection colour:black Material:Metal +pc Package Contents: 1* Bluetooth 5.0 Digital Amplifier Board 1* shell 1* screwdriver 1* power cord Notes for use: the power switch on the board is standby switch, and the machine is in standby state with low power consumption after the switch is turned off. To