When the system pressure reaches the lower limit, the power supply is automatically switched on and the pump starts to work. Features: Made of high quality material for durability and stability. It is suitable for self-priming pumps, jet pumps, garden pumps, water pumps, etc. When the system pipeline pressure reaches the upper limit, the power supply is automatically cut off and the pump stops working. Totally automatic control without manual operation., Manufacturer: Duanthry