Bluetooth Wireless Retro Microphone Handset for Mobile Phones 1. Function: Supports Bluetooth 5.0, hands-free calling (HFP v1.5), and headset profile (HSP v1.1) 2. Working Voltage: DC 4V 3. Battery Capacity: 200 mAh 4. Charging Time: Approximately 4 hours 5. Talk/Playback Time: Up to 12 hours 6. Charging Input: DC 5V, 300 mA 7. Operating Frequency: 2404–2479 MHz 8. Effective Range: Up to 10 meters (line of sight) Usage Instructions: 1. Power On: Press and hold the function button until both blue and red LEDs flash. 2. Bluetooth Pairing: Enable Bluetooth on your phone, search for “NFXSL”, select it, and wait for the blue LED to flash steadily—indicating successful pairing. 3. Answer Call: Press the function button once when an incoming call rings. 4. End Call: Press the function button once after the call ends. 5. Reject Call: Press and hold the function button for 2 seconds, then release. 6. Redial: Double-click the function button or press and hold it for 2 seconds. 7. Power Off: Press and hold the function button until the red LED lights steadily. 8. Charging Indicator: Red LED lights during charging; turns off when fully charged, and blue LED stays on.