Receiver is not necessary. If mouse does not work:
Make sure your computer meets the requirements for the system.
Make sure your computer is equipped with Bluetooth wireless function.
Make sure the Bluetooth wireless function on your computer has already been activated(please refer to user manual for how to set up and start this function).
Check whether the power switch on the bottom of the mouse is in the On position.
Check whether the power of the mouse is exhausted, and recharge the mouse if necessary.
Buttons: 3 (left, right, scroll)
Operation Range: 30 feet, 360 degrees
Resolutions: 1000 / 2000 DPI
Operating Voltage: 3.7V
Operating Current: 5mA
Compatibility: Windows 98/ 2000/ XP/ ME/ VISTA/ 7/ 8/ Mac OS
Recharging Line: 75 cm
Dimensions: 3.3 x 2.0 x 1.1 inch
Weight of Mouse and Package: 0.582 lbs