The Jenway 035-122 500µl quartz fluorimetry cuvette has a PTFE lid. This cuvette is used to take UV and visible wavelength measurements between 200 and 2,500 nanometers (nm). The glass is clear on four sides to take measurements at right angles. It has a PTFE (polytetrafluoroethylene) lid to help contain samples and prevents spills and evaporation.

Cuvettes are specialized test tubes, used in laboratory or field research, to hold samples for optical analysis by instruments such as spectrophotometers, fluorometers, and turbidity meters. Their size or capacity is most often measured in milliliters or microliters. A cuvette may be cylindrical in shape, but square or rectangular cuvettes are used when light refraction must be minimized. A rectangular cuvette may have four clear sides, for use in a fluorometer, or only two clear sides opposite each other, for use in spectrophotometry. The path length of a cuvette, often given in millimeters or centimeters, is a measure of the distance that light travels through a sample in the cuvette. Cuvettes are made of transparent quartz, glass, or plastic. Each material offers different advantages: quartz is best in the ultraviolet light range, glass and plastic in the visible light range, and glass yields more precise results. Cuvettes may come with a cap for containment or a stopper for sealing. Cuvettes are also called cuvets, absorption cells, or sample cells.