It is programmable to the critters you wish to deter so program 1 is rodents of all sorts, 2 is foxes & dogs & 3 is dogs, cats & birds, or you can set them all at once. There is a flashing light as well as the sonic noise & it also has a motion sensor which triggers both the flashing light as well as the sonic automatically. The chap who recommended it is only replacing his as the last intruders triggered the motion sensor & got put off by the light coming & ripped it off the wall & smashed it.
Hope this helps, my only beef is there is no setting for the slimy things!
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