Rred
Contributor
Of course you can also go to any auto parts chain (and some car washes(G) and for $2.99 buy one of those marble-sized ball compasses. Hey, they work. They don't care about tilt because they are balls, not floating on pivot needles. And being welded plastic spheres, they're really quite pressure-proof.
For telling "North" versus a couple of other directions, they're just too damned dumb and rugged to be bothered by minor problems like where they are being used.
For telling "North" versus a couple of other directions, they're just too damned dumb and rugged to be bothered by minor problems like where they are being used.