"Read More http://www.amazon.com/gp/product/B004VU95HO?tag=takingchances-21-20
Pentair 25021-0224S Small Inner Cartridge Replacement Sta-Rite System 3 SM-Series S8M500 Pool
Product Features
Small inner cartridge replacement
Fits Pentair Sta-Rite System 3 SM-Series pool and spa cartridge filter model S8M500
209-square feet filtration area
Measures 14-12-inch length by 31-inch height by 14-12-inch width"
