1. With 4 different viewing options, this level can calibrate with all 4 sides as well as show the angle and slope in percentage or roof pitch.
2. This app turns your smartphone into a bubble level (spirit level).
3. Comes with several sound effects and orientation locking.
4. Samsung Galaxy, HTC, Motorola, Xiaomi, Huawei and Sony.
1. I found this to be very convenient and works well.Good app, no prob.