MTL and DTL refer to two ways of inhaling vapor. The right choice depends on the desired sensation and your equipment.
MTL — indirect inhalation
First, you draw into your mouth, then you inhale: a gesture similar to smoking a cigarette. Tight draw, little vapor, e-liquids usually in a 50/50 ratio and with higher nicotine levels.
DTL — direct inhalation
Inhale directly into your lungs: airy draw, dense vapor, amplified flavors. Requires sub-ohm equipment and e-liquids high in VG.
Which one for you?
To quit smoking, MTL ( mouth-to-lung) vaping is generally recommended. DTL (direct-to-lung) vaping appeals to vapers who are looking for a more intense experience and larger clouds.