Unfortunately, when you order a Logitech Mouse M500 at the price of 37.60.-, it is always a Logitech Mouse M500s. you always get a Logitech mouse M500s for 32.80.- I've had this happen four times in a row here. four times in a row here. At Logitech's own site the M500 is no longer available only the M500 S with optical tracking system. However, Digitec.ch still sells the Logitech mouse M500 at the more expensive price. price of 37.60.-, but then only delivers a Logitech mouse M500s which only costs 32.80. I have ordered the Logitech Mouse M500 and always received the Logitech mouse M500s, I have explicitly ordered the M500, optical with laser and always and always got the cheaper M500s. The conversations with the support were always very friendly and helpful. countless times, but so far it has been of no use, the Logitech M500 mouse is being is still being sold at Digitec.ch, even though it is no longer officially available.