Works great right out of the box, comfortable in the ears and nice sound. At first with my iPhone I thought they didn't work, but discovered that I had to push past the first resistance to snap them fully into the phone and they are stable and work fine.
MM50 iP is a stereo earset for Apple iPhone which allows the iPhone users to have excellent communication capability with top of the class mobile music experience. Based on the successful launch and the popularity of the iPhone in Europe and the US, we now introduce a earset tailormade for the iPhone and iPod. Thanks to Sennheiser's expertise as a global leader in electro acoustics, the earset reproduces outstanding, professional quality stereo acoustics to ensure you gain maximum pleasure from your iPhone and iPod.