CH Hanson 03040 Magnetic Stud Finder Pack of 2

Why it's worth it

Two pocket-sized neodymium magnets that stick to the drywall screws and nails already driven into your framing. There's nothing to calibrate and nothing to power, and no way for a damp wall or a textured surface to hand you a bad reading.

Physics does all the work. Drywall gets screwed into framing, so if you find a screw, you've found a stud. Slide one of these along the wall and it clunks onto the fastener and stays put, hands-free, while you mark. Nothing to calibrate, nothing to power, and no way for humidity or a fresh coat of primer to throw the reading off. It either sticks or it doesn't.

On plaster over lath, this is the one simple thing that works. Old plaster changes density from one square foot to the next, which is precisely what confuses a capacitance sensor — owners of older houses describe electronic finders chirping across an entire wall. Magnets don't care about density. They're looking for the nails driven into the lath, and those sit where they've always sat.

From our review of 8 stud finders and wall scanners, by David Sinclair, Managing Editor

What we like

• +Physics does all the work
• +On plaster over lath, this is the one simple thing that works
• +Two come in the pack, and that's more useful than it sounds

What to know

• –You're finding a fastener, not a stud center
• –It can't help where there aren't fasteners, and it tells you nothing about wiring or plumbing