Using a magnet to find the hardware in studs is the most accurate way to find a stud. This simple, non-electric gizmo really works — much more consistently than other stud finders I’ve tried. You could make your own using a supermagnet, but this one comes ready to go with two large supermagnets mounted in a easy-to-hold device with a level. You swipe it around the wall till it pulls itself to a nail or screw underneath. Perpendicularly up/down is your stud. It’s strong enough to work through baseboards. No batteries, lasts forever.
A cool tool is anything useful that is superior to comparable items. If you think this tool is inferior suggest a better one. You are welcome to insult a tool, but comments containing insults to individual people will be deleted. Corrections of fact are always welcomed, if stated politely. Recommendations of better tools are dearly wanted and may be elevated to the front page.