A clearomizer is the transparent version of a cartomizer, designed to allow users to see how vaping actually works and how much e-liquid they have left. In reality, things are a little more complicated. Many in the electronic cigarette business choose to define clearomizers simply as transparent cartomizers, even though they’re not always built the same way. The clearomizer is usually made of thin, very easily breakable plastic, in order to remain transparent. Also most clearomizers don’t have polyfill filling, as it would make it hard for vapers to estimate how much e-juice they have left. Instead they have a wick.