Not suitable for iPhone 4S

Due to the multitude the reviews here that describe the product sufficiently, I will confine myself to a single point. With my iPhone 4S the headset is useless. In about 8 out of 10 Fälllen I got questions, where I'll be then, when I was very hard to understand. Then I turned off the headset and the phone normally by Iphone and lo and behold, no problems. "Ah, now you understand you well." Technically, I frankly myself not wirklihc explain, but as the headset was simply unusable. Am now switched to the Plantronics M50. Now the feedback is in the direction of "ah, but one understands you really well" - and proactively by the other side.