Includes booklet describing how to find your position accurately anywhere on earth. Enables the yachtsman to take a ship to any part of the earth. Used by professional, amateur and student navigators alike. This rugged, full sized instrument reads to within 2 of arc. Sometimes referred to as a "lifeboat" sextant, the Mark 3 is an inexpensive training sextant. Yet this model has taken sailors around the world, too! It is full-sized and has sunshades, but no optical magnification to help you find dim celestial bodies. Comes with instruction booklet.