Possibly one of the world's best wireless Bluetooth headsets just got even better. Sennheiser's award-winning Mobile Music wireless series now have the X-factor. The new MM 450-X and M 550-X combines the latest Apt-X technology for superb sound with a long list of premium features that make the headsets a blast to listen, talk and travel with. Why settle for less than the best, when you're on the move? Sennheiser now adds X-factor to its two new flagships in Sennheiser's wireless Travel Line series, the over-the-ear MM 550-X and the on-ear MM 450-X. The latest apt-X technology has made wireless conversations and listening to music even better. By compressing sound at a four times higher rate, apt-X® delivers a fuller and wider audio spectrum. The MM 550-X and 450-X are packed with premium features that make the headsets the number one choice for every audiophile who doesn't want to deal with background noise, but still wants to stay connected on the move. Featuring the NoiseGard 2.0 active noise cancelling technology the headsets cancel out 90% of the background noise and deliver calls in crystal-clear quality. And the praised TalkThrough function delivers clear conversation with only a press of a button activating the external microphone. There is no need to remove the headset. In spite of all the advanced technology both headsets are lightweight and foldable making them the perfect travelling companion. Another great step towards the perfect sound "You'll love these two new darlings whether you're on the move or not. With all the premium features and the latest apt-X technology, we've certainly taken another great step in our never-ending chase for the perfect sound," says Product Manager Christian Ern from Sennheiser Communications. Both headsets support most of the apt-X mobile devices as well as Mac OS X Lion. If the mobile device or the computer doesn't support apt-X the headsets will automatically switch to regular Bluetooth audio quality. All headsets have a cable included, which also comes in handy when travelling by plane. Besides high-end sound quality, the top model, MM 550-X, offers surround sound via the SRS WOW HD technology that creates a wider, taller sound, with greater clarity and a stronger bass. The headsets will be available worldwide from March 2012. Like the rest of Sennheiser's products the headsets are built to last, which is why they come with Sennheiser's special two year international warranty.