What Yellow Crane Tower, is not a soft blue, small print version is also an old version of the current market is stocked, I tell you a way, you light a cigarette, deep inhalation will be contained in the mouth, and then use your hand to pinch the middle of the cigarette, will be in the mouth of the smoke and then reverse blowing out, you will find the middle of the cigarette filter has a circle of pinhole, due to the fact that you will be blowing out of the smoke, there will be a brown substance to stay on top of it. The one with the eye of a needle is real, and vice versa is fake.