Two 2.5X 4X Eye Loupes Jewelers Watchmakers Magnifiers. This is a new set of 2 plastic eye loupes. These pocket size loupes have distortion free lenses. The shape of these loupes allows each to rest comfortably in the eye socket. You receive: One 2.5X loupe with a focal distance of 4" (101.6 mm). One 4X loupe with a focal distance of 2 1/2" (63.5 mm).