From website: This stylish, ultra-thin mouse uses Bluetooth Smart technology to wirelessly connect to your Bluetooth-enabled PC or tablet without tying up a USB port. Its ambidextrous design makes it comfortable to use in either hand, and its BlueTrack technology enables accurate tracking on almost any surface. Plus, you can use it for up to six months without having to change the batteries.
Not the cheapest according to staticice (http://www.staticice.com.au/cgi-bin/search.cgi?q=microsoft+d…), but $48.00@Officeworks, which is where I purchased it after price match ($30.36). Just note that it's quite a low profile, some people have commented negatively on this.
Good price but reviewer thinks too thin i guess it depends on hand size.