It also works on electric wires and power sources.
– Detecting of iron, steel, silver, gold, platinum, relics and other magnetic stuff
– Detecting of electric wires
– 23 different Sounds
– Vibration Mode
– Flashlight function on iPhone 4, 4s and 5
– Adjustable sensitivity
– Retina 3.5″ and 4″ support
– Calibration Mode
Every iPhone since the 3GS has a built in magnetometer.
This magentometer can be used to measure interferences in electrowaves caused by metal and other magnetic stuff.
Be sure to take your iPhone out of cases which have metal parts or magnetic buttons.
To achieve best results it is neccessary to calibrate the built in magnetometer by drawing an 8 in the air with the iPhone.