... easy to have maintenance, not easy to out off order with advantage of safe and reliableD.The Function Of Filter Units ... can be remove the sand,the suspended solids,colloid,,impurity,with large filtration area and fine effect (3-5 months)2 ... 1 piece7.Hose 1 bundle 8.Household microcomputer control system 1 piece9.Dust cover 1 piece SOURCE 50GPD RO WATER PURIFIER SYSTEM FOR COMMERCIAL USE