This GTI MM-4e colour viewing box enables you to visually measure and compare colours with the help of five different light sources. This makes a very accurate simulation possible to make sure that the results can be analysed as precisely as possible. This means that the lighting situation can be clearly depicted and metamerism can be detected. The light unit can be selected at the digital switchgear unit of the colour viewing box. The device can be easily programmed by entering a process frequency which can be activated by pressing a key.