Specifications include, but are not limited to: Required specifications for 24 to 36 compound teaching microscopes at the Oregon Institute of Marine Biology (final quantity to be determined by University after award): Binocular upright stand with standard interpupillary adjustment. Eyepieces: 10x, at least one focusable with measuring reticle, field number 19 or better. Objectives: 4x, 10x, 20x or 25x, 40x (dry), plus 100x oil objectives; phase contrast for 20x and 40x at least (prefer phase for 10x and 100x, but see next point). Planachromats or equivalent are suitable. Stage: slide holder with XY translation. Condenser: Koehler illumination with adjustable height and aperture strongly preferred. If turret condenser is available, darkfield and phase positions for 10x-100x. However: if available, slider-based phase contrast is preferred to reduce system complexity and maintenance. Darkfield is desirable for low-mag objectives. Illumination: LED with low IR strongly preferred. Because these scopes are almost exclusively used with live organisms it is important to have any heat-dissipating elements (power supply or lamp itself) outside body to avoid heating stage. Model selection should anticipate average use in classroom setting >20 hours/week with live specimens and in the proximity of seawater. Target users include novice students with zero microscope experience to undergraduate and graduate student researchers conducting research projects. Quotes should include cost of a small number of trinocular heads with C-mount adaptor.