The Bosch GMS120 is a multi-mode wall scanner designed for professionals and DIYers who need reliable detection of hidden objects behind walls, ceilings, and floors. With dedicated modes for wood, metal, and live wires, plus a graphical display and LED ring, it offers intuitive, accurate scanning for safer drilling and installation.
Key Features
- Three Detection Modes
- Drywall Mode: Locates wood and metal studs
- Metal Mode: Detects ferrous and non-ferrous metals (e.g., rebar, copper pipes)
- Live Wire Mode: Identifies live AC wiring
- Graphical Display – Shows object type, depth, and signal strength.
- LED Ring Indicator – Lights up green, yellow, or red based on proximity to object.
- Automatic Calibration – Self-adjusts for accurate readings, even over objects.
- Marking Hole – Allows precise marking of detected object location.
- Backlit Screen – Easy to read in low-light conditions.
- Audio Alerts – Optional sound signals for detection feedback.
- Ergonomic Design – Comfortable grip and intuitive button layout.
Technical Specifications
| Specification | Details |
|---|---|
| Model | GMS120 |
| Detection Depth (Wood) | Up to 38 mm (1.5″) |
| Detection Depth (Copper) | Up to 80 mm (3.15″) |
| Detection Depth (Steel) | Up to 120 mm (4.75″) |
| Detection Depth (Live Wires) | Up to 50 mm (2″) |
| Display | Graphical LCD with backlight |
| Battery | 1 × 9V alkaline (included) |
| Auto Shut-Off | After 5 minutes of inactivity |
| Operating Temp | –10°C to +50°C |
| Weight | ~270 g (9.5 oz) |
| Protection Rating | Splash-resistant (IP54) |
| Warranty | 1-Year Limited |
Source: Bosch GMS120 Manual
Pros and Cons
✅ Pros:
- Multi-mode detection for wood, metal, and live wires
- Clear graphical display with depth and type indicators
- LED ring and audio alerts for intuitive feedback
- No calibration needed—just power on and scan
- Compact and ergonomic for one-handed use
🚫 Cons:
- May struggle with shielded wires or conduit
- Not ideal for scanning through tile or concrete
- Requires fresh 9V battery for optimal performance
Interesting Facts
- The GMS120 can detect steel rebar in cured concrete up to 4.75″ deep, making it useful for structural inspections.
- The LED ring changes color based on object proximity—green for clear, yellow for caution, red for detected object.
- The marking hole above the display lets you mark the exact location of a stud or wire with a pencil.
- The unit auto-calibrates even if you start scanning over an object—no need to restart.
Lesser-Known Facts
- The GMS120 can detect magnetic and non-magnetic metals, distinguishing between steel and copper pipes.
- Rechargeable 9V batteries may cause inconsistent performance—Bosch recommends alkaline only.
- The scanner can locate studs behind plaster by switching to metal mode and finding nail lines.
- Includes a hand strap and protective pouch, making it easy to carry and store on the jobsite.
Bosch GMS120 FAQ
Who Should Buy the Bosch GMS120?
This scanner is ideal for:
- Electricians and contractors needing safe wire and stud detection
- DIYers mounting shelves, TVs, or artwork
- Renovators working with drywall, plaster, or concrete
- Inspectors checking for embedded metal or wiring
If you want a reliable, multi-mode wall scanner with intuitive feedback and pro-level accuracy, the GMS120 is a smart investment.
Final Thoughts
The Bosch GMS120 is a versatile, easy-to-use wall scanner that goes beyond basic stud finding. With its graphical display, LED ring, and multi-mode detection, it’s built for professionals who need fast, accurate results. Whether you’re drilling, mounting, or inspecting, this tool helps you work smarter—and safer.
