Which circular tube do I need?

Where are circular tubes used for?

Circular Tubes are often used in flat fixtures for decorative use. They provide a light in any direction due to its circular form.

There are 2 different kind of tubes:

If you have a circular tube with 4 pins on the same side, then it's a G10q socket.
If you have 2 pins on one side and 2 pins on the other side you have a 2GX13 socket.

When replacing the tube always stick to the wattage your currently using. The higher the wattage the bigger tube, so if you choose a higher wattage it doesn't fit in your fixture.