The black Extreme2 Bluetooth Headset from Jabra is a single ear Bluetooth headset that features dual microphones and Jabra's Noise Blackout 3.0 DSP noise reduction technology for clear calls. It supports Bluetooth 3.0 and can be paired to 2 devices simultaneously. The Extreme2 can be worn over the ear with the included earhooks or in the ear with the included standard and Ultimate Comfort eargels. The built-in rechargeable battery provides up to 5.5 hours of talk time and up to 10.5 days of standby time. The Extreme2 will automatically adjust its volume level based upon the level of environmental noise.