I waited a little to make a useful comment because I initially feared a changing batteries problem in a wireless keyboard Logitech Wireless brand: the keyboard always displayed an alarm batteries. After various manipulations, other uses of batteries and multimeter measurements, I conclude that it comes from the keyboard (I changed the batteries one after the other ...)
To return to these batteries, but good: ordered late September 2014 deadline specified = December 2024. The initial voltage greater than 1,62V. The stability over time is good.
I am very satisfied with this battery pack got a great rate. Quick delivery and careful as often on Amazon.