Logitech Mouseman M-BA47

This is Logitech Mouseman M-BA47 rollerball mouse. I just bought this "Dell by Logitech" mouse at a very cheap price around US$3.50. It was a new-old-stock (that bad photo was due to my horrible camera phone). I am connecting this to my office desktop PC.
    So, what do I think of this mouse? It is an old tech rollerball mouse. But this is good enough for my desktop since I am going to place it on a smooth flat surface. Having an optical mouse will not have much advantage over this rollerball in this case. In terms of size and design, I am so impressed with the grip provided by the rubber surface on the left and right side. It feels much more natural and comfortable compared to the Logitech M100r and heavier (therefore feels more solid). The scroll wheel functions very well like other Logitech mouses(mice?) unlike some other brands with erratic scrolling. It also has an extra button on its lower left side for your thumb to click. This can be customized using the software downloadable from Logitech's website. But sometimes my thumb accidentally clicks the button when I hold the mouse extra tight. So I prefer to leave it unassigned. As a conclusion, this is a very good mouse considering the price and if you don't mind the old rollerball tech, grab one as a spare. It is really worth it.