I bought a set of coils that the employee said would work. The first in the package did work but was flakey. The next one didn’t work saying resistance too low. I tried a third and it worked for a couple of puffs then it too gave the resistance message. None of the rest worked. When I took them back I told them that this is the second time this has happened and I didn’t feel I should have to pay for the replacement. He said since I opened them all there was nothing he could do. When I said I will pay but likely not come back all I got was, “understandable”.