E liquids come in different nicotine strengths to suit your vaping needs. The more you used to smoke, typically the higher the nicotine strength you will need to satisfy you. Vapour Days UK offer e liquids from zero nicotine strengths up to 18mg / 20mg strengths. Different kits also have an effect on the level of nicotine you can comfortably vape. Vapers using sub ohm kits tend to only use 6mg or less, whereas mouth to lung kits, designed to replicate the feeling of smoking, can take up to 18mg. Salt nicotines are also available in 20mg strengths but are smoother to vape in sub ohm kits.