First, as background, I'm a total newbie; I have yet to use an e cigarette. So be gentle. <grin> Oh - and sorry if I've posted this in the wrong place - I understand if it gets moved. I recently ordered a Kangertech EVOD kit, a couple of additional EVOD BCCs, a 5-pack of 2.2 ohm replacement EVOD heads and some juice. The order shipped today. The EVOD BCCs included in the kit come "loaded with a 2.5 ohm Standard Resistance" head. The kit also includes a 5-pack of "2.5 ohm Standard Resistance heads". (KangerTech EVOD BCC Starter Kit - MyFreedomSmokes.com) The add-on EVOD clearomizers, on the other hand, come with 2.2 ohm heads. The description provides the following guidelines: Recommended Voltage for varying resistance levels: 1.7-1.9ohm - 3.1-3.4V 2.1-2.3ohm - 188.8.131.52V 2.4-2.6ohm - 3.9-4.2V 2.6-3.0ohm - 4.3-4.7V (KangerTech EVOD Bottom Coil Clearomizer (BCC) - MyFreedomSmokes.com) While watching an unboxing vid, I remember seeing the same - or at least a similar - recommendation chart in a booklet that was included in the Kangertech EVOD kit. I stopped the vid at the time and noted that 3.7V was compatible with 2.2 ohm. I've read - and saw/heard in vids - that the Kangertech EVOD batteries fire at a "regulated" 3.7 volts. If you follow the chart above, a 2.2 ohm head would be appropriate. Yet Kangertech includes 2.5 ohm heads in their kit. <shrug> So what's up/right/better here? Is it OK for me to use both heads with my EVOD batteries? Will the 2.2 ohm heads - which, if I've got this right, should run hotter than the 2.5 ohm heads - have an effect on the usable life of my EVOD batteries? I'm just curious. I'll probably just run all of them and see what happens, but I'm still curious about what Those Who Know Better think about this discrepancy.