These magnifiers are used to check the threads in textile accurately, examine stamps, prints, engraving, circuit boards, etc. 5 kinds of the magnifiers are shown as follows. The specifications are listed in the table. Their characteristics are that they can be easily folded, unfolded and carried about. The lenses are achromatic lenses, and the double-lens combination make the achromatization perfect. The bases are etched with scales which can be used to determine the size of an object. The magnifiers with glass reticles can make the inspection more comprehensive.