Features Durable, corrosion-proof filter tank molded of color-fast material for long-lasting, all weather performance. 7-position Vari-Flo valve provides maximum flow at lower pressure drop. Large pressure sand/water drain for rapid winterizing or servicing. Flange clamp design allows 360 rotation for easy installation. Integral top diffuser ensures even distribution of water over the entire sand bed for maximum use of the filtration area. Precision engineered umbrella-fold self cleaning laterals for balanced flow and backwashing, plus easy serviceability.