Also referred to as a microtiter plate, a microwell plate, or simply a microplate, these are rectangular trays designed to be used with a microplate reader for ELISA (enzyme-linked immunosorbent assay) and diagnostic testing. A microplate contains small wells designated for sample aliquots. A plate can have anywhere from 6 to 9,600 wells.
Other plate types are made to suit the needs of the experiment at hand better. Some are black to reduce background noise, others are treated to support cell culture, others have deep wells with filters to help with extractions, and others come with a lid to protect the samples.