The biggest difference between the sets are the liquid containers. The ecigarette batteries, USB charger, wall socket charger, box and liquids, except for colour and battery size, are more or less the same. However, read carefully the description of each set.
A cartomizer is a tube with a filter (similar to a cigarette filter) with a burning filament that pre-evaporates the liquid when heated.
The cartomizers are available in many sizes, lengths, and in higher or lower ohm resistance.
The supplied cartomizer is on 2.0 ohms.
The cartomizer provides a good, strong taste and is many people's favourite liquid container.
For regular ecigarette batteries it can be a good idea to use low ohms in order to maximize vape and resistance. Approx. 1.5 to 2.3 ohms.