brand new and high quality Features: 5.0 Bluetooth-compatible version has higher transmission efficiency, and longer transmission distance. Large size black gold heat sink ensures efficient heat dissipation. With a switch, potentiometer can be used to adjust the volume,, easy to control the volume, very suitable for DIY speakers. Copper for DC connector is adopted to withstand high current and no heat. 4 x 470uF green gold capacitor guarantees the power storage capacity, and the continuous and stable power supply is the premise of good sound quality. It comes with a for DC for head with cable, which is for the input power interface of this product. Even if you don'for t have the for DC for head adapter or battery, you can connect it easily. Specification: Material: Fiber glass board + Electronic component Size: app.69 x 53 x 22mm/2.72 x 2.09 x 0.87in Color: As picture shown Quantity: 1 Pc Parameter: Model: ZK-1002L Bluetooth-compatible Version: 5.0 Chip Solution: Domestic With or Without Filter: Yes Adaption Supply Voltage: 5-24V (Optional 9V/12V/11/18V/24V adapter, high power recommended high voltage) Adapter Speaker: 30W-200W, 4-8 Number of Channels: Left and right stereo (Stereo) Bluetooth-compatible Transmission Distance: 15m(Without occlusion) for Protection Mechanism: Overheating, Short Circuit for protection Tip: To have enough output power if the audio input is sufficient and the supply voltage/current is sufficient. The power supply voltage is higher and the relative power will be larger. The speakers with different impedances will have different output power. In the for case of sufficient voltage and current, the larger the ohms of the horn the smaller the relative sound power. Please pay attention! 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 Note: No retail package. Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package includes: 1 x Bluetooth-compatible Amplifier Board