Sennheiser HD 4.50 SE Wireless Bluetooth Noise Cancelling Headphones Black Contents: Headphones, USB Cable. Used Tested Working - In Good Condition. Features: Bluetooth 4.0 and aptX technologies to deliver exceptional wireless sound quality..Connectivity Technology: Wireless NoiseGard active noise cancellation to reduce ambient noise levels improving the listening experience Intuitive ear-cup mounted controls for changing tracks and for making calls via the integrated microphone. Frequency response (Microphone) : 100 - 10,000 Hz