This digital spirit level measuring instrument is very useful and perfect for all little jobs by turning your Smartphone into a helpful level bubble. You can use this digital spirit level as a real spirit bubble level like Johnson Level, Empire Level, Stabila Level and others brands. This app is a tool used to indicate how parallel/level or perpendicular/ plumb a surface is relative to the earth. How to Use Digital Electronic Level: 1- Turn On Level application and place your smartphone on the surface you want to measure. 2- Wait a few moment for the bubble stable. 3- Adjust the surface accordingly to bring the degree reading to 0. 004- Double check the level reading by referencing the bubbles vials, if they are present. If the vials and LCD Dispaly do not match, your electronic level needs to be recalibrated. (You can calibrate the bubble and set its sensitivity in the settings menu.).