Was talking to a person in a vape shop saying how i wish the 0.27 coils in my K4 lasted longer. I get well under a week with them. They suggested trying the 0.4 ohm's. I did and not good. Takes 2 to 3 seconds to fire up, the 0.27' fire instantly, less vapour by my estimate only 50% and flavour reduction to the level of an Aio Ego. Oh yeah, spits too. Thought id share it. Cheers all.