I used one sheep hunting in Wyoming adjacent to Yellowstone Park.
There was lots of bear sign but never had an issue on four backcountry trips.
The hassle of setting it up was outweighed by sleeping better IMO. It is the one with two hot wires on top and the lower ground wire. added about 4 lbs to our panniers.
It may not work on every bear but whatever the percentage of bears it does is good enough for me.
