This International Standard specifies the characteristics of the following types of low-power magnifiers and gives recommendations for their selection for the inspection of surfaces.

• Single-element magnifiers of magnification typically up to ×4 (Type A).
• Multi-element magnifiers of magnification typically up to ×10 (Type B).
• Twin-system magnifiers of magnification typically up to ×15 (Type C), categorized as follows:
  • binocular, normally with a long working distance (Type C.1);
  • bi-ocular¹⁾, including those refined with stops or other attachments, for quasi-stereoscopic vision (Type C.2).
• Concave-mirror magnifiers with front-surface reflectors in powers typically up to ×6 (Type D).

This International Standard is not concerned with:

• watch-makers' loupes and spectacles;
• single-element, spherical- or cylindrical-lens magnifiers in which either the lens or the lens-mount rests on the surface of the object to be examined (this includes magnifiers provided with any form of graduated scale for the purpose of measurement);
• plastic lens sacs, liquid-filled;
• magnifiers intended for the examination of internal surfaces.

1) The distinction between bi-ocular viewing and stereoscopic viewing is defined in annex A.