For getting something to a specific angle (0-5 degrees). These levels each have an angled tongue to offset their nominal center position, this allows you to determine the true angle of a vertical surface within about a degree. I use these for more accurately setting launch rail angle for high powered rockets, but can be used for any vertical surface.

You will need these cheap bubble inserts, https://a.co/d/5YWLrJQ , they pop in after the print is done and are retained well. Just make sure they are fully seated for accurate results.