Operating the Stanley FatMax Stud Finder requires calibrating the unit against a flat, stud-free surface while holding the activation button until a ready signal appears. For accurate detection, move the sensor slowly across the wall and mark both edges of the stud to locate the center. For the full, verified instructions, refer to the Stanley Tools Support Portal How To Use a Stanley Stud Finder

The FatMax series typically offers multiple scanning depths and detection types: : Standard for most drywall.

The is an electronic stud finder designed to locate the center and edges of wood or metal studs through drywall up to 1-1/2 inches (38mm) deep. It also features live AC wire detection for safety during drilling. Quick Setup & Calibration

According to the manual, the Stanley FatMax Stud Finder 400 has several key features that make it a valuable tool for any user. Some of these features include:

: Slide the sensor horizontally in a straight line. Locating the Stud :

A user approaches a wall to hang a TV. They switch the FatMax 400 on, and the "Ready" LED turns green instantly—no holding down buttons. As they slide the tool across the surface, the display shows a clear, full-color visual representation of the stud edges. Suddenly, the device emits a distinct chirp and the display flashes red, indicating a live wire running vertically behind the drywall, allowing the user to adjust their mount location safely.