These are bottom vertical coils which work in the Aspire Nautilus mini as well as the Aspire Nautilus original tanks. The coils have an improved design and they have organic cotton which has been found to produce a better flavor and more vapor. They also have bigger wicking holes, than the original BDC version of the Nautilus coils, which also gives a richer vape as well as bigger clouds, a better flavor and better absorption. The coils can be bought in 0.4 ohm, 0.7 ohm mesh, 0.7 ohm, 1.6 ohm or 1.8 ohm depending on your preference. The new 0.7 ohm coils are the style which ships with the Aspire Nautilus 2 tank, and the 0.4ohm coils are the style which ships with the Aspire Nautilus 2S - 2.6ml Top Fill Tank.