We paired the Jabra Extreme with the Apple iPhone 3G. We tested the Extreme in a variety of situations: in a quiet office, in a moving vehicle, outside on a busy city sidewalk, and in a crowded cafe. In all situations, we were impressed with the Extreme's call quality. We heard our callers loud and clear thanks to the headset's automatic volume adjustment, which cleverly increases and reduces incoming volume. The Extreme also boasts Acoustic Shock Protection that protects the ear from sudden blasts of noise. Our callers sounded natural as well.
On their end, callers said they heard us without a problem in the quiet environment. There was a bit of static, but it was not a distraction. In the noisier situations, they could still hear the background noise, but it was definitely muffled when compared to our voice. They said we sounded crystal clear most of the time. Sometimes the voice quality would dip a little bit, but it sounded natural for the most part.
The Jabra Extreme has a rated battery life of 5.5 hours talk time and 10.5 days standby time.