Peak Scale Loupe is a typical measurement of simplicity, accuracy and low-price.
Magnification: 7x
Field of view: 24 mm
Effective apperture: 18 mm
Size: 36 mm x 57mm
Net weight: 56 gm
P.S.L. has excellent achromatic lenses (3 elements, 2 groups) and a photo-printed precise scale. It also has a focusing ring and 7 power magnification.
As all sorts of lens aberrations are avoided, you can easily read the object.
Keliner type with 3-element, 2-group construction. Accurate measurements can be made by turning the focusing ring so both object and scale can be seen.