Bought a pen cartridge and it wouldn't work with my 510 battery. Figured no big deal I know these things are mass produced in china and sometimes they can be defective. Tried to return it a few hours later and the lady told me I was shit out of luck because they cant test it to verify its defective because theres a no smoking policy. On top of that they kept the broken cartridge and didn't give me a refund or any type of store credit. Out 60 bucks and 2 car trips. They couldn't have done worse even if they tried.