Triple-Lens Illuminated Measuring Magnifier 7X Magnification, .780" Lens Diameter.

General Purpose Scale— Measures any radius from  1/16" to  3/8"; angles up to 90° in 1° increments; lengths up to  1/2" in 0.005" increments; lengths up to 1 mm in 0.1 mm increments; and line widths of 0.001", 0.002", and 0.003".

Use these pocket-size magnifiers alone to magnify, or with photo-etched scales to magnify and measure. Precision-ground corrected glass lenses provide distortion-free images and are adjustable for clear focus. Available in standard and illuminated models with a triple- or double-lens system. Furnished in a case.
Triple Lens Measuring Magnifiers
Also known as Hastings Triplet, three separate lenses are bonded together to form a compound lens for sharp images. The next step up in image quality is a microscope. Magnifiers are 1 3/4" high. Illuminated magnifiers have a 5 3/4" long handle, and use two AA batteries (sold separately).