Ok, I know the rebuildable purists out there will say using pre-built coils is cheating BUT it's helluva handy! One day I may well build my own coils but in the meantime I'll use these! A BRILLIANT product - plenty of options to try various set-ups. WAY cheaper than buying stock coils! A BRILLIANT product - there's even a handy 3-way nano-sized, T-shaped screw driver! Am just glad Go Smoke Free sell them. Always a super-quick ordering and delivery service.