Not a resistance setting, a voltage or wattage setting. Resistance is fixed by the coil (ohms law) - most devices sold in the past couple years allow users to set a desired wattage, they read the resistance of the coil and determine the appropriate regulated voltage required to meet that wattage.
The past year has seen an explosion of temperature controlled devices, but they require coils made out of specific metals (Ni-200 or stainless steel). Ni-200 is almost unilaterally a bad choice, one of those getting too hot releases noxious chemicals - so if the control chip in the device malfunctions (there have been reports of this) it is possible to have health repercussions. Stainless steel has been a good choice, overheating will just burn the cotton wicking - not good for you but compared to breathing air in urban centers for years it's not going to make a dent in your overall health.
The past year has seen an explosion of temperature controlled devices, but they require coils made out of specific metals (Ni-200 or stainless steel). Ni-200 is almost unilaterally a bad choice, one of those getting too hot releases noxious chemicals - so if the control chip in the device malfunctions (there have been reports of this) it is possible to have health repercussions. Stainless steel has been a good choice, overheating will just burn the cotton wicking - not good for you but compared to breathing air in urban centers for years it's not going to make a dent in your overall health.