I use the TFV4 with NI200 on the build deck running at 0.1 ohm coil set at 420F and 20 Watts. It works perfect for me. Never gets hot unless I take like 5 hits one right after the other. The triple coil got way to hot for me so I just make my own coils. 0.1 ohm. somewhere around there. I just purchased the Steam Crave Aromamizer RDTA with the 2 post design. Made dual coils at 0.06ohm and it isn't hot either. 420F at 30 Watts. I hate hot vapes, so that is why I don't use the prebuilt coils from TFV4. Just my preference.