Sennheiser has re-invented the ear bud with their “Twist to Fit” design found in the MX 90VC. Rather than just letting the ear bud rest on the bottom of the ear, the MX 90VC has an extension above the bud piece, topped with a rubber wheel, that wedges the earpiece into the ear. The earpiece is inserted at an angle and twisted while in place, causing the wheel to roll along the upper edge of the inner fold of the ear, wedging the driver into place.



Link: Digitaltrends