For those who want flexibility from their Bear Sentry.
One Expansion Pack can increase the area protected by a Backcountry fence from 25 square meters to roughly 65 m2 (in a hexgonal layout).
Add more to outfit a group or camp with friends. The energizer can support up to 20 km of wire so almost any sized enclosure is possible.
Because the Bear Sentry system is modular, Expansion Packs can also convert a Base Camp model into a Backcountry.