Perimeter Technologies Four Pack Dog Fence Batteries for Invisible Fence R21 or R51 Receiver Collars (4-Pack) ProfessorZ The update’s key improvements are

The update’s key improvements are to the motor and shooting wheels

Good Combination of Speed

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Wi-Fi Direct

- Motor: 48V 500W Brush-less Geared Motor

Perimeter Technologies Four Pack Dog Fence Batteries for Invisible Fence R21 or R51 Receiver Collars (4-Pack) ProfessorZ The update’s key improvements areBrand: Perimeter Technologies Features: Pack of 4 batteries. The Perimeter Brand Invisible Fence Replacement Battery is the best solution for keeping your Invisible Fence Brand system operating safely. Compatible with R21, R22, or R51. Less Expensive than the original. Publisher: Perimeter Technologies Details: The Perimeter Brand Invisible Fence Replacement Battery is the best solution for keeping your Invisible Fence Brand system operating safely.