Contour Design RollerMouse Free3 Wireless, Ambidextrous, Rollerbar, RF Wireless, 2800 DPI, Black Contour Design RollerMouse Free3 Wireless. Form factor: Ambidextrous. Movement detection technology: Rollerbar, Device interface: RF Wireless, Movement resolution: 2800 DPI, Buttons type: Pressed buttons, Buttons quantity: 9, Scroll type: Wheel. Power source: Batteries. Product colour: Black