2 Water Pressure Gauge Kit - 30 PSI - Euro White 2 - Hole size: 2.0625 (53mm)
A pressure gauge operates by sending a low amperage current through the gaugess meter to ground via a sending unit with variable resistance. The resistance of the sending units increase or decrease with the changes in pressure, temperature, etc...
As the senders resistance varies, the amount of current allowed to flow through it to ground changes and the meter deflects, showing the change in pressure.
Anti-scratch glass lens
Plastic Cases for corrosion resistance and long life