Seeking advice on an open/short circuit finder, wire tracer

I am considering getting an open/short circuit finder, for some test on an automobile. I've seen a number of short circuit finders, are there more than 2 open/short circuit finders?

For anyone who maybe wonderng how short/open circuit finders work (http://askville.amazon.com/tone-generator-locate-short-circuit-electrical/AnswerViewer.do?requestId=5912724) (this one in a home environment, and an idea on how to use a short circuit finder (http://inliners.org/tech/tech6.html) to find a short circuit.


1) What features should I look for?

2) Do you have any other advice/suggestions on a short circuit finder? type, manufacturer, model etc

3) Do you know if the current leak detector, only detects heavy current leaks?

Thank-you in advance,