They are working great for me, of course, when using 6+v you have to be really really careful to let go of the button super fast!
I use them on my Chuck at 6v, GG at 6v and GGSS 7.4v. So far, I haven't lost one yet, nor are any of them showing any signs of burning/scorching the filler. I am using the same 5 out of the first box in rotation on all 3
devices. I consider my
vaping to be on the heavy side.