The distance between the base of the cuvette and the centre of the photometer light beam is defined as the centre height (Z). The centre height can vary depending on the manufacturer and the type of photometer, which is why Sarstedt offers UV cuvettes in two different centre heights (Z = 8 mm and Z = 15 mm). If customers do not know the exact centre height of the photometer, this information can be requested from the device manufacturer.