This is a rechargeable NiMH battery that replaces the collar battery in the 1125DT No Bark Collar.
Replaceable RECHARGEABLE battery:
We recommend sending your unit in for a collar battery replacement.* If you do replace a collar battery yourself, there are a couple of things to keep in mind when changing a collar battery:

1) Be careful not to pull any other wires off the circuit board when removing the old battery.
2) Make sure the rubber gasket seal is properly fitted around the receiving unit to ensure that there will be no water leaks.
3) Try not to over-tighten the screws when putting it back together or you might crack the plastic casing, also causing water leaks.

This may be a different version of the battery you have, but it will still work in your unit.

Note: Due to upgrades, the part received may be a different shape from the original in your system, but the voltage will be the same.

*Replacing the collar battery yourself during the warranty period of your unit may void the warranty. Contact DT Systems Directly if you are still in the warranty period for further details.