High Tech Pet Rechargeable Backup Battery for Humane Contain TX-1 Electronic Dog Fence Transmitter Keeps your Humane Contain TX-1 transmitter working during a power outage for up to 2 days TX-1 transmitter automatically recharges the battery TX-1 transmitter is a component of Humane Contain HC-8000 and X-10 electronic fence systems Sealed lead-acid construction 12-Volt; 800 mAH capacity