10 parameter should be paid attention to select flow switch

1. Pipe size, Thread type;
2. The voltage and max current, which the flow switch connect to
3. Medium temperature, 
4. Max Pressure of the liquid pipe;

5. Pipe material,
6. accuracy
7. Protection level
8. will it need anti explosion proof?
9. will the liquid be corrosive;
10. will there be much suspended solid in the fluid?