The GU3311 is an Automatic Mains Failure controller. This controller allows the generator to automatically start and stop when the power fails as well as monitor the mains supply.
Harsen GU3303 (BP5S Only)
The GU3303 is a manual controller designed for smaller and less complex generators. This controller has all the basics built into it but does not offer AMF. Intended for manual use only.
Generac Evolution (GAS Gensets)
The latest controller offering from Generac, the evolution efficiently manages the generator and the automatic mains failure to automatically start or stop the generator.