A spirit level. Hold any of the phone's four sides against an object to test it for level or plumb, or lay it down on a flat surface for a 360° level.

- Calibrate any side independently
- Calibrate relatively (another object surface) or absolutely (earth gravity)
- Show angle in degree, inclination in percent or roof pitch
- Sound effects to calibrate without looking at the phone
- Install on SD
- Orientation locking
- No permission required at all