20 nicotine cartridges to refill the regular sized e-cigarette. Each cartridge is equivalent to approximately 12 to 18 tobacco cigarettes depending on your smoking habits. Please choose the level of nicotine you would like. High is recommended for those who are heavy smokers or those who smoked rolled cigarettes, Medium is for those who are moderate smokers, Low is best to use as a reduction in nicotine intake leading up to the use of No-Nicotine cartridges.