Feature:1. Bluetooth 4.2 version, compatible with all mobile phones and Bluetooth adapters on the market. The transmission distance is about 15m/49.2ft in an open area, and it supports automatic connection to the paired devices and automatic playback of music.2. Support USB sound card, free drive, plug and play (under normal lithium battery power supply). The maximum working current is 5V2A, powered by a regulated power supply of 5V2A or above, the sound quality will be better.3. Two speakers of 28 and 310W can be connected respectively, and 45W and 410W speakers are recommended for stereo output.4. Builtin USB charging port, it can be powered by a USB port or a 5V adapter, which is convenient for using.5. When installing the Bluetooth board, try not to place the Bluetooth antenna close to metal parts, so as not to affect the transmission distance.6. The built-in dual 5W power amplifier circuit must not be used with another power amplifier! The outputs of the two power amplifiers cannot be connected in parallel or the negative poles connected together, otherwise the power amplifier chip will be damaged.Specification:Item Type: Stereo Amplifier Module Material: PCBMaximum Working Current: 5V 2ALength: Approx. 40mm/1.6inWidth: Approx. 20mm/0.8inHeight: Approx. 12mm/0.5inPower: 5Wx2Bluetooth Version: 4.2Bluetooth Module Operation: Turn on the mobile phone's Bluetooth, scan the device, find "DW-CT14+" and click connect.Instruction:3.7V lithium batteries(not included) are recommended (lithium batteries need to have a protective plate!).With USB charging port for lithium battery charging, USB port can also be used as power supply port or 5V adapter power supply, can not use dry battery, charger, multi-function transformer and other unstable voltage, current power supply..Package List:1 x Stereo Amplifier Module 3 x Connection CablesNote:1. The charging interface of this product is in current‑limiting charging mode without charging management. Please be sure to use a lithium battery with a protective plate.2. It will automatically shut down after 10 minutes in the standby state, and need to be powered on again.3. It is not recommended to directly use the charger to supply power through the USB socket. The USB charging port is mainly used for charging after the battery is installed on the Bluetooth board. This charging port has a current‑limiting resistance.