I see a huge number of e-cigarette types, what are the differences?
Answer:
E-cigarettes come in all shapes and sizes. If we had to categorize e- cigarettes, it's best to start by looking at the inhalation method. Many of the smaller e-cigarettes have a limited airflow, meaning they (like traditional cigarettes) are often inhaled mouth-to-lung (often referred to as MTL, or mouth-to-lung). On the other hand, there are devices that have a large airflow. These devices are often inhaled directly into the lungs (often referred to as DL, or direct lung). This latter category is similar in some ways to smoking a hookah. In this latter category, we often see large batteries that can provide more power, sturdier tanks that can handle this power, and produce more vapor.
Of course, within these two categories, there are many different devices, each with their own advantages and disadvantages. There are also devices that fall between the categories (often labeled RL, or restricted lung), and there are always exceptions. For example, there are smaller devices that are closer to a DL in terms of inhalation, and larger devices that are closer to a cigarette in terms of inhalation (MTL).
Pod systems are widely used these days. These are often compact e- cigarettes that use pods (and a fixed resistance). These systems are often handy and generally operate on inhalation force, eliminating the need for a fire button. These systems are easier to use and require fewer actions than coil systems.