PID Retrofit KIT for Gaggia Classic Pro & Classic & Home
[KIT-GG]

It works - meaning there's a noticeable difference which simply translates to taste. Any temperature-related bitterness as a result of the original bimetallic's wide temperature swing has been eliminated. I've owned my Gaggia Classic (with other, sound modifications) long enough to know this is an improvement. It should be noted, (though I'm certain you know), that the boiler heater in the Gaggia Classic has the capacity to increase boiler temperature during the pull, or throughout the duration of a pull. If this were not the case, a PID wouldn't make sense. I believe that a PID for this machine is a good investment. Five stars. Highly Recommended.