Invisible Fence Brand Collar Compatible, Rechargeable Batteries and Charging Base Circuitcell - Invisible Fence Brand Compatible Rechargeable Battery Includes Rechargeable Battery : Does NOT Include Charger Compatible with Invisible Fence R21, R22, R51 and Microlite Collars Lasts 30 days on Single Charge Low Cost - 80% Savings / Environmentally Friendly / Convenient - No Battery Plans