The Nautilus X by Aspire is a fantastic leak-resistant tank.
We offer one coil option for this tank. These coils utilize Aspire's proprietary 'U-Tech' coil technology. Long story short this means that the coil has 2 holes on the top of it; one to allow air into the center of the coil and a second to allow the air/vapor through the mouthpiece. This genuinely makes this a very leak resistant tank, and in an upright position, I would argue, it is leak proof.
The coil option we carry is the 1.5ohm coil, which is rated to run from 14watts to 22watts.
Nautilus X coils are sold in a pack of 5.