all i can tell you is i tried to save money by purchasing this mouse. my boyfriend lost partial mobility of his hand a week into using this THING.... and seriously he could not move his hand without it hurting. i found it very uncomfortable and difficult to master using myself... i say forget saving money and save your hands! spare the extra ten bucks and buy a better mouse. stick with logitech, they have awesome mice USUALLY- just don't buy this particular design. it is awkward!