Krave500 offers the highest puff efficiency at up to 500 puffs. This unique electronic cigarette is a 1-piece unit, meaning there are no atomizers to screw in, no filters to replace, and no batteries to recharge - it is ready to smoke right out of the pack. Once you are done with your Krave500, simply dispose of the entire unit. Available in menthol leaf flavor and in a mid 14mg nicotine level. Overall puff efficiency is estimated and can vary depending on size, duration, and profile of inhalations.