国产69久久精品成人看,天天做天天爱天天综合网2021,亚洲国产婷婷香蕉久久久久久,欧美性xxxxx极品娇小

High efficiency filter, it is a filter medium to remove water suspended solids, microorganisms, and other fine particles, and ultimately reduce water turbidity, water purification effect of a filtering device. Commonly used filters are quartz sand, activated carbon, anthracite, manganese sand and so on. Widely used in agricultural irrigation, chemical, petroleum, metallurgy, mining and other industries.