SENNHEISER D 10 USB ML - US Single Ear Headset Wireless Type: DECT Part: 506418 Operating Time: Wideband: Up to 8 hours Narrowband: Up to 12 hours Distance: line of sight: 590' In typical office building: 180' Headphone Frequency Response: Wideband: 150 Hz - 6.8 KHz Narrowband: 300 Hz - 3.5 KHz Weight: Ear hook version: 0.78 oz. Headband version: 1.76 oz. Microphone Frequency Response: Wideband: 150 Hz - 6.8 KHz Narrowband: 300 Hz - 3.5 KHz Color: Black