You may be confused between the HFS2 (no failsafe assembly) and HFS3 system.
The HFS2 is supplied with the same controller as the HFS3 (labelled HFS3). But does not come with the following:
1. Dash gauge
2. Gauge cable
3. Flow sensor assembly
4. Hall-effect flow sensor cable.
It is "not" possible to use gauge from other makers.
What is the serial number of the controller?