The mAh rating is a measure of the capcity of your battery. A higher number will last longer.
Ensure the voltage of the battery you wish to replace is comparable.
Some (And only some) devices don't like rechargable devices as they output a lower voltage (1.2V in the case of NiCd, don't know about NiMH). As a side note, Rechargable batteries have a lower internal resistance.... so they get hotter when you short them out ;-)
Neil Thomas, AKA MiniBobF
