The beauty of this design is that it lies flat on the paper and you simply look through it. While made for reading details on nautical charts it is endlessly useful in the home, office and shop. No focusing is necessary, and it can be comfortably viewed with both eyes from a wide range of angles and distances - no squinting. The 'bright field' optical design has the effect of collecting light from all around the loupe and directing it right onto the surface you are looking at. At 14 oz. it also makes an attractive paperweight.
The compass rose (degree markings), traditionally used for marine navigation, is authentic (it adds a salty touch just right for day dreaming of the open sea). Made of flawless crystal-clear acrylic rather than glass - which would be too heavy, expensive and prone to defects. It delivers a 50% increase in magnification over its smaller kin in the 4X Surface Loupe (24T02.12)