Imagine using a dozen stud sensors at the same time. That's the basic idea behind the Franklin ProSensor (though it looks more like a grout float than a stud sensor). This tool monitors an entire 7-inch area of a wall in 13 different locations, so you can see both edges of the stud at once. It scans to a depth of 1-1/2 inches and — because of its length — can detect multiple objects at the same time. No tedious calibrating is required; you just place the tool against the wall and it starts working.