First, there are three basic types of hand-held compasses: lensatic, mirror, and orienteering. The mirror compass is commonly referred to as the Brunton Pocket Transit, named after the company that first manufactured it. The main difference that set this particular compass apart from it's peers is the fact that it uses magnetic induction damping to settle the needle rather than the traditional fluid damping. It is a very accurate compass that is often used by survey teams, and has also found use in the US Army for manual sighting of field artillery.



An orienteering compass is generally either a protractor or thumb compass. These are both made with a rotating housing such that they can easily be laid on a map to take bearings without performing any type of pencil and paper calculations. The compass is laid on the map aligned with magnetic north, and the housing is rotated such that the direction of travel arrow points to the desired point. It's not meant for pinpoint accuracy, but rather speed and convenience since orienteering is a competitive, timed sport.

Next, the lensatic compass is the type used by the modern day US Military for their general navigation activities. It is one of the older tools in their inventory, but due to its rugged construction, ease of use, and dependability, it has not been replaced by any higher technology tools. Of course, GPS is the preferred form of navigation, but it should always be verified with manual calculations, and in the event that equipment malfunctions or a signal cannot be found, the lensatic compass is the go to.

It's called a lensatic compass because of a small magnifying lens on the rear sight. This lens offers a greater degree of accuracy when taking sightings and measurements from the bezel. This is one of the primary reasons it is preferred over other types, as accuracy is often important when determining location in a tactical environment. The lensatic compass is somewhat of a jack of all trades, as it can perform the tasks of both the mirror and the orienteering compass fairly well, as well as provide a greater degree of accuracy if time and care are taken.