Reads 2.1ohm on Evic, fires on Evic no problem. Put it on an Ego 650 and the light goes dead until i remove it. Ive built an Aro head at 2.1ohm and a Vapeonly BCC head at 2.1ohm and neither fire on the Ego. What i really dont get is, i have stock Evod heads at 1.8ohm, that read 1.8ohm, and work on the Ego. Its a 30 gauge kanthal 8 turn standard coil, nothing fancy. I built the Vapeonly BCC up because i figured maybe the Aro was shorting in the Ego but not the Evic for some reason, guess not