Stereoscopic microscopes use two separate optical paths angled slightly apart to produce a three-dimensional image at relatively low magnification, typically with a long working distance. Compound microscopes use a single optical axis and achieve much higher magnification for thin-section specimen work. This functional and structural difference places them in separate SITC headings, and the distinction is important because duty rates at the HTS level may differ.

A stereo microscope with an integrated camera generally retains its classification as a microscope if the optical microscopy function is the essential character of the complete unit. The camera is treated as an accessory. However, if the digital imaging system is the dominant component by value and function, reclassification under a different heading could be argued — importers should review the specific configuration with a customs broker.