Poolmaster 13115 Replacement Filter Cartridge for Sundance Double End 120 6540-488 Filter The corresponding Pleatco number is PSD125-2000 and the corresponding Unicel number is C-8326 The top of the replacement filter cartridge is 1-1/2 male slip fitting and the bottom is 2-1/2 open with beveled edge Break-resistant bands keep pleats separated for greater flow, filtration and add longer life to cartridge High quality spun bonded polyester material for exceptional water filtration Premium grade polyurethane and plastisol end caps