Type: Earlink. Headset Main Application (Chinese not always supported): Universal Hearing Aid Application: Mobile Operating Principle: Closed Audio Response (TX): 10Hz - 20kHz SPL: 99 dB, Driver Size: 40mm, THD: Not available, Noise Cancellation: No, Other Weights: Not available, Cable Type: Coiled, Length: Not available, Connector: 3.5mm, Built-In Microphone: Yes, Wireless Bluetooth connection: Yes.