YiHi SL Class V2 with single Samsung 30T 21700 and a SMOK TFV16 with a TFV18 RBA, Dual Coil, 3mm 24g SS316L, 0.16Ω Build. TC is at 219 °C for 426.2 °F because °F settings are funky on this Mod. This TFV18 RBA has Amazing Flavor! I use 8.5mm coil legs to get the coils high enough for the Airflow Slots adjustments to be effective. Anything less and the coils and cotton block the airflow and make it too restrictive for a proper DTL Vape. I like the SMOK TFV12 on this Mod because its 28mm base diameter is a perfect fit and, with the bubble glass, its capacity is 9ml.
I did not like the reddish red-orange o-rings that come with the TFV16 (and also the TFV18), so I searched and searched for black ones, but could not find them anywhere. I decided to try my SMOK TFV12 Prince Black o-rings and they fit and seal perfectly. They have to stretch a bit on to get them started, but that's what make them work. If you have a TFV16 or TFV18, you can use TFV12 Prince o-rings on them, but you have to get the real SMOK brand TFV12 Prince Bulb Pyrex Glass Tube #2 that comes in a plastic twist-off top container.