text: Yes, it's a tiny mirror compass. It is my backup now because it's so tiny, but also because I know how to use it, and it is pretty full featured. In fact, I used this when I did my outdoorsy times, and I climbed mountains while wearing it.
  This one has another feature rarely found, in that it has a safety pin on it. You clip it open to your pack strap and can look down to see your heading. It works.
  I also carry this because I had a DEET explosion and sorta ruined my old mountaineering version of the same one. I cleaned it enough it works and is in my other backup bag. The one I actually carry is a Brunton sort of knockoff of it and not as good as the old one. It's called the 27 LU Compact Pin-On Mirrored Compass or the Trooper and when you can find it isn't too expensive ($25), but in addition to being not perfectly awesome, can be hard to find.
  There are other small, ruggedized compasses like the matchbox style that may also make you happy. Skulk around and see what is out there.
  A tool like a compass is no good without training, and practical experience using it. CWG can get you that. Start planning for CWG's day/night land nav training course in October.
  We will also bring a selection of compasses to the the training weekend, so you can try out some of the others and see if anything else thrills you.
  The first thing you need to land nav in any useful way is a magnetic compass. Simply being able to orient yourself to where north is, or keep yourself on track no matter the terrain and lighting gets you way ahead of the game.
  Squad leaders are briefed, with a map and protractor out during the brief. Consistent, well-communicated position information is critical to operational planning and actions.
  The first thing to consider is that you likely work with others. You all want to be speaking the same language, and to be able to brief in things like declination changes to everyone at the same time.
  Speaking the same language is basically one of mils vs degrees. A circle can be broken up any number of ways, and a number of them are not useful for our purposes so we shall not speak of them. Degrees are very common, well-understood, but not used by most military forces.
  Instead, they use mils, which is just short for milliradian. That's an SI-derived unit of angular measure which is a thousandth of a radian. A radian is the angle subtended at the center of a circle by an arc that is equal in length to the radius of the circle. Yeah, don't worry about that, as you don't need to know. There are about 6283 milliradians in a circle, but again, you don't need to know that, exactly.
  Because it's an inconvenient number. Instead, armies have standardized on various other rounded off versions. The WARPAC generally agreed to call it 6000, the Swedish Army (they make the best compasses, so we care) had 6300, someone had 6280, and many others. This does matter because NATO settled on a nice easily-divisible 6400 a while back, so many good military surplus "mil" compasses are surplus because they are some other weird, antiquated number.
  That matters for compatibility. If you are in a team and they say to march at a certain heading until you reach a road, your 6000 mil compass is pointing a different direction than their 6400 mil one.
  If you work with a team of people who probably carry compasses, start with asking them what they suggest. Then, read carefully, and check my last section. Because if they say "you can get it at WalMart" then be really, really careful.
  There are lots and lots and lots of types of compasses. But there are really only about 2-1/2 kinds that are in common use these days for land navigation in the west.
  Clearly, most compasses can be considered a capsule attached to a baseplate but here we mean a particular style of compass which is: