The compass is a vital part of everyone's tactical gear, whether you're camping, hunting, hiking, geocaching, or paintballing. Why? Simple. It doesn't run on electricity, it doesn't need to track five satellites orbiting 25 miles up in the sky, and it won't get ruined if it gets wet. Bottom line: of all your tactical gear, it's the one that will get you out of the worst problems and it's always dependable.
History of the Lensatic Compass

While the exact time and date is debatable, many people credit the earliest compasses to the Chinese somewhere near 1040 AD. There no proof that the discovery was used for navigational purposes, but it is apparent that the properties of a magnetic draw to the north were noticed and documented. References to navigation with compass are found as early as 1119 AD -- again, by the Chinese.

Modern Tactical Gear | Lensatic Compass
Move forward ~889 years and we have the modern compass in everyones' bag of essential gear. They still consist of basically the same components, all centered around a magnetic dial dampened by electromagnetic induction. They're almost idiot proof: they contain needle locks to keep the dial from moving around when not in active use, they're water-proof, shock proof, and are designed for use from -50F to 150F. Many manufacturers also use tritium and phosphors to allow for navigation in darkness. While most tactical compasses are painted green, they are also available in camouflage and black.

Other Modern Compasses
A gyrocompass is a direction-finding instrument that operates in a similar manner to a gyroscope, by using a spinning wheel to determine north in relation to the rotation of the earth. The advantage? For one, it finds true north, not magnetic north. Magnetic north differs depending on where you are in the world and the behavior of local geomagnetic fields, most of which do not cause the compass to point to the north pole. True, or map north, is just that. Follow the line to true north and you'll end up at the top of the world. Also, gyrocompasses are not affected by ferrous materials which makes them ideal for use on ships.

Solid state compasses are a group of small electronic sensors that detect magnetic fields in relation to magnetic north. They are usually found in pairs or trios, and simply provide an analog signal that changes with their orientation. That signal must be interpreted by the component's main electronic device. These types of compasses are usually found in cell phones.

Regardless what type or brand of compass you buy, put some time and effort into picking it out. You never know when it will move from the back of the line to your primary means of navigation.