It used to control and protection for the normal operation of the unit

0-5v - 0-300 psi for our digital pressure gauge =>

Package included:
1 x sensor
1/8 -27 NPT   
Actual item is silver (stainless steel)  in color

You need dual alternators to run any decent sized Hydrogen Generator system and the pump required to feed it at idle as a single alternator will not put out enough amps - even a high amp one