Those look interesting, thanks.
Essentially I find that the Nanos mute the flavor a bit and are prone to leaking after re-use. The Phoneix bottom coils for 808s unfortunately leak as well (I have Phoenix bottom coils for 510 connection that work flawlessly but for some reason the same is not true for the 808 ones). So I need something that are not prone to leaking, easy to fill and work with my slim Volt battery.