Davis Deluxe Mark 25 Master Sextant [025]Mark 25 Sextant #025 The top of the line Davis plastic sextant, the Mark 25 features our Beam Converger mirror, sometimes referred to as a "full horizon mirror". A special coating is applied to high quality optical glass to allow the user to see through this mirror, yet still pick up images as faint as low light stars. The Mark 25 is illuminated by a long life LED and made of an upgraded plastic that is very stable. Comes with instruction booklet.