The first set of AA batteries in the Logitech Cordless mouse mentioned last month have finally expired. Seeing the batteries came with the rodent I'm not sure how long they had been in store. I've replaced them with freshly charged NiMh batteries so we'll see how long those last. I must say the mouse isnt as pleasant to use as its Microsoft relation. The buttons are quite long and slope down the nose of the mouse like a car bonnet (Hood ? ) This means the lightest click position is right at the front edge of the mouse, on the Microsoft the buttons are a good 15mm higher. I'll persevere with it but might be tempted when Microsoft bring out their version, nothing here yet. Any Microsoft cordless/optical mice on sale in the US ?