Added PID to my Gaggia Classic Pro for a fraction of what the kits sell for. Please read my comment! : r/espresso
Gaggia Classic with PID - 2008 ( USED ) | Coffee Forums
Gaggia Classic Pro PID kit in action | PID controller mod - YouTube
PID KIT for Gaggia Classic Pro & Classic & Home w/ pre-infusion [KIT-GGP] - $199.50 : Auber Instruments, Inc., Temperature control solutions for home and industry