Lights- What is the difference between the fluorescent light and the metal light? Do they work together, or does one replace the other?

They are both illumination tools for the polar scope.

The fluorescent light is a plastic light attached to the end of the polar scope tube. After shining a light on it (such as a headlamp or phone flashlight) for around one minute, it will glow in the dark.

The metal light, as the name suggests, is made of metal. It uses two LR754 button batteries and is screwed into the threading part of the polar scope. You can also adjust the brightness by rotating the bottom part.

They replace each other, so choosing either one is fine.