This is a comparison meter where the reference surface is provided by phosphorescent material. The field of view shows areas of light from the subject and the reference material, where the two match a number is shown, this is used to find the exposure settings printed on the outside tube of the meter.

The meter is based on a patent by Friedrich Reiss.

This meter is closely related to the Chromophot and uses a phosphorescent reference surface. The meter is placed on the viewing lens, the finder then shows a luminous area and a number of small circles, the circle just a little brighter than the background indicates a value which is used in a table to find the exposure setting. The meter was priced at 19/6 for cameras with an f4.5 or f6.3 lens, an adapter was available for f7.7 lenses.