Thanks to this thread I went by Radio Shack and picked up two CR1632 batteries for $12.78. I replaced the one on my key fob and measured the voltage of the existing battery versus the new battery. Battery rating is 3 V. Existing battery = 2.84 V (95% SOC) New battery = 3.24 V (108% SOC) How long would the existing battery have lasted before starting to fail? At +$6.00 I cannot think of a good reason to wait and find out? I will change my wife's when she gets home tonight. It will be interesting to see the voltage on this one since it is seldom used.