PS-01, PS-01A, PS-01B, PS-01C, PS-01D Pressure controllers are designed to prevent the pump from dry running which is the main problem to the jet pumps with pressure tank and other accessories. However, if there is a leakage in the pipeline, it can alleviate the water pump start too frequently.
The working principles and applications of the pressure controllers are all the same but the appearances are different for the customer preference.
Moreover:
PS-01, PS-01A, PS-01C cannot adjust the pressure to start.
PS-01, PS-01A, PS-01C and PS-01D have membrane inside.
PS-01B has the screw inside of the cover to adjust the pressure, but this item without the membrane inside.
PS-01D has the screw on the topside to adjust the pressure.
The inside membrane of the pressure controllers like a small-sized pressure tank, if there is a drip on the water pipe, it can alleviate the water pump start too frequently. 
Model - PS-01
Voltage - 220-240V
Current - 10А
Connection diameter - 25mm
Model - PS-01А
Voltage - 220-240V
Current - 10А
Connection diameter - 25mm
Model - PS-01B
Voltage - 220-240V
Current - 12А
Connection diameter - 25mm
Model - PS-01C
Voltage - 220-240V
Current - 12А
Connection diameter - 25mm
Model - PS-01D
Voltage - 220-240V
Current - 10А
Connection diameter - 25mm
