Davis Instruments Mark Master Sextant Deluxe 0. 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 an instruction booklet. Specifications for Davis Instruments Deluxe Mark 25 Master Sextant: Manufacturer: Davis Instruments Color: Black Package Contents: Davis Instruments Deluxe Mark 25 Master Sextant Davis Instruments 025: Mark 25 Master Sextant Deluxe