Specifications include, but are not limited to: 1.1 Binocular with standard interpupillary adjustment. 1.2 Eyepieces: 10x, at least one focusable with measuring reticle. 1.3 Zoom range: at least 5x (ideal range is ~0.67-5x). 1.4 Stand: base with focusing arm (see below); fine focus not required. 1.5 Illumination: transmitted-light base with glass plate and sliding/tilting mirror (also require black/white plate for incident illumination use); stage must be useable with a 10-cm vessel or standard-size well plate. 1.6 Light source: cold light (LED or externally-lit gooseneck) strongly preferred, switchable between incident and transmitted, any heat-dissipating elements (power supply or lamp) outside body to avoid heating stage. 1.7 Model selection should anticipate average use in classroom setting >20 hours/week with live specimens and in the presence of seawater. Users range from novice students to undergraduate and graduate student researchers.