The compass is essential kit for any survival pack. For use in the Military, Bushcraft, Hiking or any other outdoor activity. Your compass can be a lifesaver and will greatly improve the safety and efficiency of travel. The compass is a navigational instrument for determining direction relative to the Earth's magnetic poles. The compass has a magnetised pointer marked on the north side, which is able to align itself with the Earth’s magnetic field. A compass can be used to calculate heading, used with a sextant to calculate latitude or used with a marine chronometer to calculate longitude. As a navigational aid it has only been recently supplemented by global positioning systems or GPS for short, however you should always have a compass as a back up to your GPS .