A little wonky at at first. It has a (intentionally?) loose fitting ring around the threads that wouldn\'t allow it work. Maybe it works with some devices, I don\'t know, but I\'m certain lose it if I ever do need it. Other than that it\'s cool.
I love the fact that I can now put the cartridges I love on my huge ego battery so I can vape longer out without having to charge my old standard battery multiple times while out. Only problem I had was that it took a lot longer than projected delivery date to get here.