Well I have an Explorer, but its the old 1500 sample version. I picked up the Optical for my second system and found its a 2000 sample. So I use it for the primary mouse on my main machin, and have made the explorer sit on the secondary. As soon as the Explorer dies (shortly I am expecting, its starting to jump a lot and loosed connection whenever I plug something else into the USB. So RMA time I guess)
So in reality I got TWO MS OPTICAL TECH MICE.