They work great for me with my 5v passthrough. They get kinda hot but who cares, not burning down the house hot.
It was driving be NUTS hearing people in vaping heaven talking about there 6v dual coil experience. When I put one on my Rstack or silver bullet at 6v nothing happens. I figure it has to be the prtection circut on my batteries. I hope i have some luck with high drain. What does work well at 6v are the boge cartos that came with my revalution V2 3 ohms on my multimeter.