5" x 13-5/16" Aquiform-Infinity Spas Filter PRB50-IN-M, C-4950, FC-2390, 03FIL1600 5" x 13-5/16" Accent Spas Filter Antimicrobial PRB50-IN-M, C-4950, FC-2390, 03FIL1600 5" x 13-5/16" Top Open 2-1/8" Bottom Open 2-1/8" PRB50-IN-M, C-4950, FC-2390, 03FIL1600