TeckNet M002 2.4G Nano Cordless Black Optical Mouse - 2.4 GHz -1600dPi - Nano USB wireless receiver - 2010 Edition (AA BATTERIES NOT INCLUDED)
Bought this as I thought that if it was no good I hadn't wasted too much money. Very surprised by its look, weight, size, responsiveness and range of operation. (My model has no on/off switch underneath - switches off with the laptop - good feature). Much superior to similar big brand models and excellent value for money.
I would buy another one except for the battery cover, which appears to be badly designed or flimsy. I dropped the mouse and the cover closing tag broke and cannot be replaced so I have to use it without a cover, which means that when it is dropped (keeps sliding off the laptop if it's moved etc) the batteries dislodge, which is a real pain.
Apart from that, a first class product - especially for more careful owners!