Walabot DIY 2 – Visual Stud Finder & Wall Scanner for Drywall. Detects Wood & Metal Studs, Plastic & Metal Pipes, Live & Non-Live Wires

Why it's worth it

This pairs with your phone and draws a live picture of what's behind the drywall — studs, metal and plastic pipe, and wires both live and dead, down to about four inches. It's the tool you want before opening a wall, not before hanging a picture.

Every other tool here tells you something is back there; this one tells you what. Radio imaging builds a map on your phone screen instead of a beep, and it separates wood studs from metal, metal pipe from plastic, and live wires from dead ones. Before you cut in a new outlet or open a bathroom wall, that distinction is the whole ballgame. Owners describe spotting an electrical run sitting right where they'd already marked a hole.

Depth is the other advantage. It reads to about four inches, which covers stacked drywall, heavy skim coats, and walls that have been resurfaced a couple of times. A finder that tops out near an inch has nothing useful to say about those. If you keep getting muddled readings in an older house, more range is often what you were missing.

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

What we like

• +Every other tool here tells you something is back there; this one tells you what
• +Depth is the other advantage
• +Setup is less annoying than a phone-connected tool has any right to be

What to know

• –The app is where the complaints pile up
• –It's also the most expensive tool here by a wide margin, and the manufacturer limits it to drywall and plywood