Horizontal contrast between solid and liquid stops: Hand sense, the stop slider of the solid stop agent is not as delicate as the liquid. In portability, the solids are small and convenient to carry. In the production, the solid is not poisonous and tasteless, two minutes can make a pair of invisible deck, after the production is finished can be used. The liquid has a certain pungent smell, which needs to be made in a ventilated environment, which can be used when it is finished.