The laserliner star finder plus is an electronic device with lcd display for the easy detection of ironsolid bar and live electrics within wall structures the user guide on the lcd screen makes it accurate and reliable to use the scanner has an auto calibration which automatically adjusts the device immediately to different surfaces an acoustic signal sound and visual will signal on locating of objects supplied with 1 x 9v battery depth range iron solid bar up to 75cm live electric up to 4cm