SportDOG rechargeable replacement Li-Ion battery  3.7V 160mAh for use with the following  Receivers:

This battery can be used with:

The battery come partially charged from the factory, but will require a full charge (2-3 hours) before the first use. The rechargeable Lithium-Ion (Li-Ion) batteries are not memory sensitive and do not require depletion before charging. When storing the unit for long periods, remember to regularly give batteries a full charge (2-3 hours). This should be done once every 3-4 months. Includes a rechargeable battery, rubber gasket seal, and screwdriver.