Lithium Ion battery technology offers three times the gravimetric density of nickel metal hydride technology.In simple terms, this means lighter batteries with increased run times. Replacing batteries not only provides the ability to instantly renew the collar receiver"s power supply, it also provides a consistent duration for battery life . With proper use of the on/off switch the Impi Bark Control battery will last upwards of two years!Compatible With:IMPI-BARK: IMPI Bark Control CollarPTPFS-003: Perimeter PCC-200 Comfort Contact ReceiverPet Stop UltraElite ReceiverPet Stop Elite SWPet Stop Ultra Elite Series 2 Receiver