Direct-to-lung (DTL) or Sub Ohm tanks refers to a style of vaping wherethe vapour is inhaled in a continuous flow through the mouth and into the lungs. Typically, DTL vape tanks have a more restricted airflow and produce less vapour than direct-to-lung tanks. These tanks also use lower resistance coils than tanks used for MTL vaping, and require more power. The coils in DTL tanks also have larger coil ports (holes in the coil) to make it easier for the coils to absorb thicker e-liquid.
One of the keys to DTL vaping is the coil and the airflow. If a tank can be used with both high and low resistance coils, and the airflow can be adjusted from tight to open, it can usually be used for either mouth-to-lung and direct-to-lung vaping. DTL tanks work best with e-liquids with a VG:PG ratio of around 70:30. Direct-to-Lung vaping is best suited for intermediate to experienced vapers who enjoy larger clouds of vapour. DTL tanks are best used with more powerful batteries capable of higher wattages than MTL batteries.