https://www.youtube.com/watch?v=E-PUlC0hWUU It is a ceramic donut shaped coil with nickel wire leads attached to it. How would i find out the TCR of the ceramic? I doubt that i can account for the nickel leads, and whatever soldering they use to attach the leads to the ceramic, so i know it wont be super accurate. I would just like to have a nice smooth somewhat accurate TC vape for this atty. Also: the link for the coil head i bought (2nd link) shows a picture of the coil but with black ceramic donut shaped wick on top of it, I'm sure that contributed to your confusion @chunkybutt200. The coil underneath the wick is what i am referring to, almost identical to the vapin donuts in RIP's video link above.