Specification Model: KN321 Technology: BT5.0, A2DP, AVRCP (Receiver Mode Only) Working Range: Up to 10m / 33ft (without any obstructions) Pairing name: KN321 Charging time: 2 hours Working time: RX: 6 hours; TX: 5 hours Battery Type: Lithium Polymer (200mAh) Size: 44 44 12mm Weight: 18g Features: 1. This extremely portable and lightweight wireless audio transmitter and receiver is the ideal wireless audio solution for every situation and use ;2. Transmitter Mode: Wirelessly stream audio from a non-Bluetooth TV, home stereo or CD player to Bluetooth headphones or speakers ;3. Receiver Mode: Wirelessly stream audio from a Bluetooth-enabled phone, tablet or computer to a wired stereo, speakers or headphones 4. Just flip the switch to switch between transmitter and receiver modes. Connect easily with advanced Bluetooth technology and 3.5mm audio cable (included). 5. The ultra-portable audio streaming power supply KN321 is only 44 mm (1.73 inches) wide and only weighs 18 grams (0.63 ounces), yet has powerful wireless audio streaming capabilities. Put this transmitter and receiver in your backpack or laptop bag and take it with you on the go effortlessly Power on: Press and hold the power on/off button until the LED is on Power off: press and hold the power on/off button until the LED is off Charging: Use a DC-5V charger and a micro usb charging cable. The red light is on when charging. When the battery is fully charged, the blue light is on. Switching mode: 1) RX: receiving mode, indicator light: blue LED2) TX: transmitting mode, indicator light: red light Receiving mode: pairing name: KN321/KN319, find KN321/KN319 in the mobile phone Bluetooth settings for pairing, pairing The blue light flashes 2 times per second during the process, and the blue light flashes once every 3 seconds after pairing is successful. How to use: 1) Plug one end of the audio cable into the audio input of the speaker and the other end into the audio of the KN3212) Make sure it is in RX mode (blue light flashing). Find the pairing name in the phone's Bluetooth settings: KN321/KN319 and click pairing. TX mode: TX mode will automatically search for other Bluetooth receiving devices (such as Bluetooth headsets, Bluetooth speakers, Bluetooth receivers, etc.), the red light flashes twice per second during the pairing process, and the red light flashes once every three seconds after successful pairing. How to use: 1) Insert one end of the audio cable into the audio output of the device, and the other end into the audio of the KN321/KN319. 2) Confirm that it is in TX mode (red light flashes). The KN321 will automatically search for a Bluetooth headset or Bluetooth speaker to pair. What's Included: 1* Bluetooth 5.0 Audio Transmitter/Receiver Adapter 1* Micro USB Power Cable 1* RCA Cable (PS: If you don't choose "with RCA cable", RCA cable is not included) 1* 3.5mm AUX audio cable 1* User Manual