Starter Kits generally have a draw that mimics that of a cigarette. Often referred to as Mouth to Lung kits and can be used with High to Low nicotine strengths.
Sub Ohm Kits are generally more cloudy devices and aimed at lower nicotine and those wanting serious vapour production. Often referred to as Direct to Lung kits.
Pod systems are all in one devices and come in refillable, pre filled disposable up to more cloudy versions.
Disposables are small all in one devices pre filled with liquid. No filling and no fuss.
Separate Batteries for external battery devices. 18350, 18500, to the more popular 18650, 20700, 21700 and 26650 sizes.
Mod (External Cell) that take separate batteries that are recommended to be charged outside of the device in a dedicated battery charger.
Mod (Built in Cell) have the battery built in and can be USB charged in the device.
Stick Batteries are often known as pen batteries.
This could be the coil is not in place correctly. Make sure the coil is seated as it should and try again.