Best Permeter Sensor and Placement

Or you could just set it to when they are physically touching the car right? Becuase I heard the range was only adjustable from 3 feet from car to 3 inches from car...........that seemed too sensitive to me too.....if someone just happened to walk by it could go off.

The perfect thing I would want is for it to be set up to go off only if someone is touching the car with enough pressure to make it seem suspicious........is this possible? If this thing is set up right, do you guys reccomend it? Any other suggestions/tips/advice

Any idea where I can get it for a good price?

Thanks.