Tanks are simple in design, they hold e-liquid that is then absorbed by the coil, the coil heats up the e-liquid and vapour is produced. There are mainly two different styles of tanks, you have MTL (mouth to lung) and Sub-Ohm or DTL (direct to lung). MTL tanks such as the nautilus 2, give the user a smoking sensation. They tend to use 50/50 e-liquid which gives off little cloud and gives the user a throat hit. DTL tanks usually use small amounts of power, so you wouldn’t need a big device to get them working. Sub-Ohm tanks are quite a bit different, they tend to use higher VG e-liquids, this gives the user bigger clouds and smooth inhale. Due to them using higher VG e-liquids, they usually need more power so a device that can do around 50 watts minimum is required.