This app is detecting various metals using the built in magnetometer by measuring differences, fluctuations and interferences of the magnetic field. It also works on electric wires and power sources. Features - 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 - Adjustable sensitivity - Retina 3.5" and 4" support - Calibration Mode Every iPhone since the 3GS has a built in magnetometer. This magnetometer 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 necessary to calibrate the built in magnetometer by drawing an 8 in the air with the iPhone. This app is intended for entertainment purposes only and does not provide true metal detecting functionality.