CAUTIONS! This app requires 'MAGNETIC SENSOR' on the device. Do not install devices without 'MAGNETIC SENSOR'. CALIBRATION Check your devices that isn't being affected by a magnetic objects or not. Maintain magnetic field strength between 30~60μT. Then make an accurate eight-figure multiple times as in the image below.If calibration does not work well, rotate the device several times to left, right, top and bottom. If the calibration still fails, there may be a mechanical problem with the device. Features • Show calibration notification • Google map service • Horizontal level • Device slope • Magnetic field strength • True heading • Latitude, longitude • Adress