100+ lb yellow-eyed male Chesapeake retriever works fine for me.  I do have
a small sign on each window saying "Beware of the Dog" that warns the unwary
as they approach my van..Before adding that warning, I encountered some
startled and irate people who stopped to look inside that ole Hippy
Van..only to be greeted by the snarling beast behind 1/4" auto glass...

  Don't need no key..don't need no alarm...just a bowl of water..

 Don Hanson