Pentair 24851-9000 21-Inch Upper Half Tank Shell Replacement Kit Sta-Rite System 3 Pool and Spa Filter Upper half tank shell replacement kit Fits Pentair Sta-Rite System 3 SM, SMD-Series modular media and D.E. pool/spa filters Also fits Pentair Sta-Rite System 3 SD, SS-Series D.E. and sand pool/spa filter models S7D75, S7S50 Includes all decals and labels Measures 21-inch