Spare part Transparent cover plate for optical refractometer prism with illumination is suitable for all optical refractometers in our catalogue.
Under the sun icon is located a microswitch for the illumination control.
It is not necessary to use the illumination during each measuring. Use it just in dark rooms, basement and so on. Under normal lighting has this cover plate similar optical properties like the standard transparent cover plate without the illumination.
Battery life is approx. 5000 uses