I bought this mouse recently to replace an older packard bell wireless one.
This is worlds apart from the old one.
It seems to always be ON. You don't need to click it to bring the pc out of sleep, you simply move it.
When i realised, after having received it, that it is not rechargeable, i was not too happy.
However, having had it for 2 months and constant use, the battery levels have hardly moved.
The truth is that i now prefer it as is and without a bulky power transformer.
One other thing, a couple of times, on start up, i got a warning pop-up saying that the range is not good.
Not sure what that was about because the mouse was still operational and i simply clicked on ok.
An excellent product overall, highly recommended!