not trying to knock it, at all, cause it did help me quit smoking entirely - walked down the nicotine til zero and just flavor, pretty easy after that - but those things started giving me insane heart palpitations like a donkey kick in the chest.
granted I was basically using it as a filter to breathe all my air through, and one of those big honking ones, but still, never felt like I got punched from inside the heart smoking 2 packs of cowboy killers a day, not like that anyway.