This product can find out metallic materials such as nails under wall without damaging cross wall with a pendulum of strong magnet.You can draw a vertical line at the place where this product found a point.This product also can be used as a level.This product can find out metallic materials such as nails under wall without damaging cross wall with a pendulum of strong magnet.It is so light and compact easy to carry.The thickness of the wall that can be detected is up to 15mm.● ABS resin (main unit)● Acrylic resin (windshield)● Strong magnet (pendulum)● 4-line acrylic vialSensitivity 0.50mm/m=0.0286°Precision ±2.50mm/m=within±0.1432°