I'm not sure what the frequency range is for ursual hearing, but at that level, you can be sure they will know you are there. If it is operating in their hearing sweet spot, they will not like it much. Animals tend to avoid things that screw up their senses, and for a dog this would be about all they could hear within about 50 feet. Might be a bit painful on those auditory organs, too.

Tain't heavy, maybe a pound or less with batteries. Less if you use them lithiums. Won't last forever, though.