TrustedReviews looked at the Sennheiser PC120 and PC30 Headsets

At first look, you'd think I was wearing a Bluetooth headset, but the cable is a bit of a giveaway. It's a small one piece device that clips on to your ear. The headphone portion of the device pivots around 180 degrees so that it works on either ear. The ear piece fits inside your ear and provides most of the support, while the shroud around your ear just gives it that little bit extra.

Sennheiser PC120 and PC30 Headsets Review