The innovative, curved design of the Memorex 98311 Wii Expanded Range Wireless Sensor Bar allows for a more expansive gaming playing area with fewer dropped signals. The Memorex 98311 Wii Expanded Range Wireless Sensor Bar is ideal for group games like Rock Band and Guitar Hero and Mario Kart. What It Is And Why You Need It: Innovative, curved extended range sensor provides a wider and further playing area Low battery indicator Power-saving sleep modes.