A:AnswerHello katnip, The M220 uses an infrared (IR) optical LED that is invisible to the human eye. If you're not sure whether your mouse is turned on, check the ON/OFF switch located on the bottom of the mouse. - Richard from Logitech
A:AnswerHey there TP! Unfortunately, the M220 SILENT mouse comes with our Nano receiver, not our Unifying receiver, so you would not be able to use the unifying software to connect multiple devices to just the one receiver. -Weston from Logitech.