Invisible Fence Northwest provides an electronic perimeter to keep your pet contained. A collar on your pet, sometimes used only during an initial training period, reacts with the installed electronic border, training the pet not to cross the line. The system can be used both indoors and out. The company claims its collar is the lightest available, called Micro-lite. While dogs and cats are the primary "customers," Invisible Fence Northwest has also installed systems for donkeys, pigs and other larger animals. Training for your pet is included, typically lasting about three weeks. Free consultations are provided. Owners Dick and Patsy Pattison lived on Mercer Island when they started this business in 1992. The company's <a href="http://www.invisiblefencenw.com">website</a> provides links to other pet services.