"Mouth to Lung" (MTL) and "Direct to Lung" (DTL) vaping differ primarily in the inhalation technique and the type of e-liquids used. Mouth to Lung (MTL) Vaping: This method involves drawing the vapor into the mouth first and then inhaling it into the lungs. It's akin to the way one smokes a cigarette. MTL vaping is often associated with higher nicotine strength e-liquids and a higher PG (propylene glycol) ratio. PG contributes to the 'throat hit,' which can be too harsh for direct inhalation. MTL devices usually have tighter airflow, mimicking the resistance felt while smoking a cigarette. Direct to Lung (DTL) Vaping: In this style, the vapor is inhaled directly into the lungs, bypassing the mouth-holding step. This method is more similar to taking a deep breath. DTL vaping is typically paired with smoother, High-VG (vegetable glycerin) e-liquids, which are less harsh on the throat and produce larger vapor clouds. The devices used for DTL vaping generally allow for more airflow, facilitating a direct and less restricted inhalation into the lungs.