This is a bubble level app that uses a smartphone with a built-in orientation sensor. Keep your phone flat by horizontal or vertical adjustment of the bubbles between the center of the double lines. Billiard tables, constructions, carpenter, You can use this app anywhere.
Note: Some phones will give different sensor readings based on the hardware used by the manufacturer. And some phone bad sensor (or sensor error) will show an inaccurate result. The latest version of the app Bubble level download for android.