DESC: So how did they get a complete satellite receiver into a device that measures 3.7 x 2.2 x 0.6 inches? By using an advanced satellite/terrestrial internal antenna that allows the device to receive signals from anywhere. The device is light, too, weighing in at just 4.5 ounces. The unit's full-color, 180 x 180 TFT display, as well as a user-friendly interface, make it easy to save and delete content. In addition to making it easy to find the music you want to listen to quickly, the interface lets you build your own playlists right on the device that consist of XM radio content and your own digital music. Another cool feature is the Helix's built-in memory buffer, which allows you to save an entire XM radio song even if you decide to save it in the middle of the song. The Helix's internal memory supports up to 50 hours of saved content.