That depends on where you're buying them from - the atomizers that drewsworld (nhaler) carries are 5.2 ohms, the ones that eastmall sells are 4.5 ohms (this is what they claim, I haven't tested them personally). For any resistances outside of those 2, check the
thread in the modders forum or drop me a PM, I still do custom orders from china for non-standard resistances in both 801 and 510 styles.