I bought a bluetooth mouse for my daughter's laptop for Christmas ( I could could swear I remember her Dell D520 having bluetooth when I bought it... I guess not).
Anyway, I returned it today at Fry's Electronics. I wanted to find another cordless mouse but did not want one that has one of those huge bluetooth or USB dongles that gets lost, or has to be removed to put the laptop in its case, or gets broken off.
Solution! I found a Logitech VX Nano mouse which uses 2.4GHz wireless. It comes with a USB transceiver dongle which when plugged into the laptop protrudes from the side less than 1/4 inch (pic attached below). This means she can leave the dongle plugged in permanently as it does not interfere with putting the laptop in it's case and doesn't protrude far enough to get broken off.
As for operation, I did not install the CD drivers that come with it which allows web updates and programming five buttons. Used without the CD drivers you plug in the USB dongle, install the batteries, and it just works.
