Ultrasonic pest repeller

We're starting out a little bit different this year. Last year even with our fence all the way around it we still had raccoons and rabbits that were digging their way under our fence. We even put bells on our fence thinking that this will scare them away. I think they just like the music that the bells made. We bought an ultrasonic pest repeller. We're hoping this will take care keeping the critters away so we don't lose our garden this year.