most compasses are optimised for the hemisphere in which you will be to make it easier to adjust for magnetic north
some compasses are global and can be used anywhere in the world
compasses can lose magnetism or reverse polarity if stored close to a microwave device (EPIRB, smartphone) or magnetic material such as Apple iPhone MagSafe, etc
compasses become inaccurate if used near other compasses, magnets, batteries, metallic objects, etc
most compasses with glow in the dark markings are phosphorescent and require initial light then last for some 4 hours, some military grade compasses use radioactive material and do not need to be primed by light and will glow continuously for around 7 years
some compasses have an adjustment screw to manage magnetic declination map error, others you need to adjust manually
some compasses are marked in 360 degrees and some are marked in the more precise 6400 mils (milliradians) which is what is used in the military for artillery purposes
some compasses are “lensatic” which means they use a magnifying glass set at 45deg angle to the compass to more accurately line up a bearing line
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lensatic military compasses
the tritium versions of thee are generally the best compasses for night time use
these are used VERY differently to base plate or mirror compasses
Cammenga Lensatic Tritium USGI Compass
compasses with mirror sightings
other high quality compasses