Microsoft Wireless Mobile Mouse 3500. It includes a Nano transceiver that sticks out less than a centimeter from the USB port, so it can remain plugged into the computer at all times. The Wireless Mobile Mouse 3500 is a bit smaller, so people can pick the best fit for their hand size. It will be available in Loch Ness Gray and Dragon Fruit Pink.

Features

• BlueTrack™ Technology: Microsoft BlueTrack Technology combines the power of optical with the precision of laser for remarkable tracking on virtually any surface.
• Plug-And-Go Nano Transceiver: Leave the Nano Transceiver plugged in when you're on the go, or stow it in the mouse.
• 8-Month Battery Life: Use your mouse without power interruption for up to 8 months on a single battery. Battery status indicator tells you when battery power is low.
• ON/OFF switch: Conserve more battery power by turning your mouse off when not in use.
• Comfortable in Either Hand: Use your mouse with your left or right hand--ambidextrous design makes it comfortable either way.
• 3 Year Warranty: Limited Warranty and License Agreement available here.
• Computer/Operating System: Windows® 7, Windows Vista®, Windows XP (excluding Windows XP 64-bit), Mac OS X v10.4 --10.6
• Battery Powered: 1 AA Alkaline Batteries required (included)