This is one of those things that you really want to have rather than taking chances.
It detects pipes and cables inside the wall, so you don't find them accidentally.
Green means no object detected. Yellow means metal object near the sensor. Red means a metal object detected in the sensor area and red flashing light means that a live wire/conductor is detected.
The first time this goes over the area it gives a rough estimate of the position of the metal, keep passing it over to increase accuracy.
KIT LIST: multidetector, manual, 3x AAA batteries, metal box