Halt will work IF you manage to get it in their eyes or nose. It will also work on you if the wind catches it and blows it back in your face. My advice for dog country is to get a small air horn (marine supply stores usually have these although there are some marketed for bicycles). These horns can put out 110+ db and that is enough to bring dogs to their knees and cover their ears (dogs have very sensitive ears). This will stop the dogs from getting close enough to use the halt and that is a good thing.