The ‘bright field' optical design of this magnifier collects light from all around the 1 ⅛” thick loupe and directs it right onto the surface you are looking at. The beauty of this deceptively simple device is that it lies flat on the paper and you simply look through it. No focusing is necessary, and it can be comfortably viewed with both eyes from a wide range of angles and distances. And at 16 oz. it also makes an attractive paperweight.