Nova's, iClears, Evods and Protanks - Not one bad head yet. Come to think of it, i haven't replaced a head yet due to failure. I have popped a few doing stupid stuff like putting a 1.8Ω Coil on my bolt with stacked 350's, lol lasted about an eighth of a vape! i do dry burn my coils every couple of tanks or so to keep the crud off em tho.