A cuvette is a small tube of circular or square cross section, sealed at one end, made of plastic, glass, or fused quartz (for UV light) and designed to hold samples for spectroscopic experiments. Disposable plastic cuvettes are often used in fast spectroscopic assays, where speed is more important than high accuracy. Glass cuvettes are typically for use in the wavelength range of visible light and fused quartz tends to be used in the UV through NIR ranges.