I have a 2-dog collar and transmitter that I need to replace the batteries on. It would appear to be a costly venture to send the collars in for battery replacement, and I am wondering if there is anyone here who has replaced the batteries... I understand that the collars and transmitters are sealed to be waterproof, and am wondering how much of an issue it is to replace the batteries and reseal successfully? I am also wondering where you get the batteries? Marc.