Professional 3-in-1 wall scanner detecting live cables, metal pipes and wooden studs up to 120mm deep.
The Bosch GMS 120 is the go-to wall scanner for electricians, plumbers and general builders who need to know what is behind a wall before drilling. Its three detection modes cover live cables, metal pipes and wooden studs, while the illuminated ring provides instant traffic-light feedback — green for safe, red for danger.
The Bosch GMS 120 is one of those tools that every trade van should carry. A few seconds of scanning before drilling can prevent cutting through a mains cable, puncturing a water pipe, or missing a stud entirely. The consequences of not scanning — a live cable, a flooded ceiling, a failed fixing — far outweigh the cost of the tool.
The drywall mode detects wooden studs and joists behind plasterboard and is the correct mode when fixing into stud partition walls. The metal mode picks up ferrous and non-ferrous metals including copper pipes, steel beams, and rebar — useful on masonry walls where pipes may be buried in the plaster. The live cable mode detects energised wiring up to 50mm deep. Switching between modes is a single button press; for a thorough pre-drill check, running all three modes in sequence takes under a minute.
The illuminated ring around the display changes colour as you scan: green when the area is clear, yellow when approaching a detected object, and red when directly over it. This is far more intuitive than numerical readouts, particularly when working overhead, in dim conditions, or one-handed. The centre-finding function identifies the mid-point of a stud, giving you the precise drill position for a secure fixing.
The GMS 120 requires calibration on each new wall surface — hold the tool against the clean wall area and press the calibration button. This sets the baseline for that specific substrate. Like all wall scanners, it is a detection aid rather than an absolute guarantee: deep cables, complex wall construction, and overlapping services can all affect readings. In high-risk situations — chasing for new circuits or drilling next to known services — a scan should be supplemented with a visual check and a careful pilot hole.
The Bosch GMS 120 is the professional wall scanner that tradespeople across all disciplines rely on. Its three detection modes, traffic light feedback, and centre-finding accuracy make it an essential safety tool for anyone who drills into walls regularly.
| Detection Depth (Ferrous Metal) | 120mm |
|---|---|
| Detection Depth (Non-Ferrous Metal) | 80mm |
| Detection Depth (Live Cable) | 50mm |
| Detection Depth (Wood) | 38mm |
| Modes | Drywall, Metal, Live Cable |
| Power | 1x 9V battery |
| Weight | 270g |
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