Features . Small inner cartridge replacement.. Fits Pentair Sta-Rite System 3 SM-Series pool and spa cartridge filter.. 100-square feet filtration area.. Measures 11-inch length by 30-1 2-inch height by 11-inch width.. 3 - 100 sq. ft. Repl. Media - Inner for S7M120. Dimension - 11 x 11 x 31.25 in.