We originally did quite a bit of research for the compasses we include with our courses.
The Suunto company had some that fit what we are looking for with 2 degree separation markers, turnable bezel, easy to read directional arrow on the base, and since we don't know where in the world it will be going, a "global balancing system."
If you buy your compass in the geographic area you live in, there isn't going to be an issue. Ordering them from the internet, unless they take into consideration where it's going to, may have an issue.
In order to get an accurate reading from a compass, the compass needle needs to be "balanced" in the capsule, so it does not drag on the top or bottom of the capsule. But, because the horizontal and vertical components of the earth's magnetic field vary considerably in different locations, a compass needle that "balances" perfect in North America will drag or stick in South America. As a result of these magnetic variances, the compass industry has divided the earth into 5 "zones".
Suunto has developed a patented Global Needle that will perform perfectly with needle tilts of up to 20 degrees. This allows a single compass to be used effectively in all 5 of the earth's zones
We obviously buy ours in bulk. We've used their M-2 and M3.
There are a lot of internet sites that sell Suunto compasses. You can locate a dealer here:
http://www.suunto.com/en-US/Where-to-buy/Best,
Shawn
