MTL (mouth-to-lung) vape devices are devices that are built for vapers who prefer a tight draw which is comparable to smoking a cigarette. Using a device like this requires you to take a pull with your lips (or mouth), and then inhale thereafter. These devices typically require the use of liquids that contain higher nicotine levels and have a lower VG/PG ratio (below 70/30). They are generally used with freebase nicotine liquids with strengths of between 9mg and 18mg, or nic salt liquids with strengths of between 15mg and 50mg. Until recently, pod devices only offered a Mouth-to-Lung (MTL) option. These days however, pod devices may be used in Direct Lung (DL) and Mouth-to-Lung (MTL) applications.
Pod-style vape devices are typically of 2 types:
1) The pod and coil are inseparable and purchased as a unit
2) The pod and coil are separated and purchased individually. With this variant, you only need to purchase the pod when it has become defective or if you prefer to store different liquids in different pods (giving you the option of switching between flavours at any time). You will however need to replace your coils when the need arises
Please note that generally speaking, for lower resistance coils, lower nicotine strengths are recommended. The opposite is also true. Use of lower resistance coils (below 0.6 ohm) for higher nicotine liquids (above 6mg-8mg) is not recommended