The dial on the back is for the sound of the locator. if the arrow on the dial is pointing up to the top then for example it will "bleep" even if the ferret is 12 or 14 feet away. the further anti clock wise you turn the dial the closer you will have to be to the ferret to hear the bleep.... Thats as best as i can explain it!!!! hope it helps! GOOD HUNTING!!!!