I wish all apps could be as well written as this one! No Ads  no permissions  hardly takes up any resources  extremely accurate  retains its calibration well  HUGE display that's well designed and clear and easy to see  it even autorotates to display the correct level depending on orientation of the screen. Tried some other similar apps and their dismal performance made me think my Nexus5X might just have very poor sensors. Nope - they were just hopeless apps and it took this one to prove it! I set up a level surface using a digital level and my traditional spirit levels until I was sure it was just right  and then used that surface to calibrate Bubble Level app. That was weeks ago and it's still spot on. Now recommending it to everyone I know.
July 01 2016