Ego batteries.
Yeah, I know that sounds dumb but my wife destroys about two a month in her purse...have yet to kill a delivery device since we learned about tank cracker juices, and since I pay for everything and I'm a cheap(censored) 99% of our juice comes from MBV with zero complaints, Egos it is. I won't buy a mod, because I'd have to buy her the same mod, and then when it breaks I'd have to replace it...hooray twist!