400 to 600 V

400 to 550 V

400 to 500 V

400 to 450 V

at a very high pressure

at a high pressure

at a medium pressure

at a low pressure

To limit the power factor

To limit the starting current

To limit the voltage

To limit the energy

9000 hrs

8500 hrs

8000 hrs

7500 hrs

The diameter of the tube

The gases in the tube

The length of the tube

The colour of the tube