The Zone VI coldlight should have a recepticle for the sensor that can then be attached to a Zone VI cold light stabilizer. This stabilizer functions differently from voltage stabilization. With the use of a cold light intensity can fluctuate apart from voltage variances due among other factors the temperature of the source. The Zone VI stabilizer works on a feedback of the measurement of the actual light output from the source. I don't believe that the stabilizer is manufactured any longer, even though it was a very good device. I have one that I wanted to use with my D2 omega, but replaced the enlarger with a Saunders 4550 XLG with variable contrast source. I think that this feature is now an integral part of the cold light enlargers manufactured by Zone VI (as I recall).