This standard BS ISO 8578:2012 Microscopes. Marking of objectives and eyepieces is classified in these ICS categories:
37.020 Optical equipment
This International Standard specifies the format for the marking of data or symbols for optical characteristics on microscope objectives and eyepieces and the positioning of the data. It makes recommendations for the marking of additional information, particularly colour coding of rings designating the magnification of objectives and the immersion media with which they are used.