Nano Receiver : Small enough to plug in once and leave connected.
Wireless : Plug in nano receiver and go wireless. 2.4GHz reliability and performance.
Nano Slot : Convenient nano receiver storage for when you need it.
Comfort Grip : Smooth, rubberized grip designed for comfort and control.Specification:

Compatible with USB 2.0 or 1.1
Compatible with Windows 98SE, ME, 2000, XP, Vista, Windows 7
Adjustable optical sensor from 800-1200 DPI
Automatically power saving, make battery working longer
Working range within 10 meters (30 Feet)
ON/OFF switch: turn on or turn off mouse power
Weight: 3 Oz
Package Includes:

Wireless Mouse X 1
Nano receiver (comes stored inside mouse)