Poolmaster 13134 Replacement Filter Cartridge for Pro Clean 125 817-0125P Filter The corresponding Pleatco number is PWWPC125-4 and the corresponding Unicel number is C-8413 The top of the replacement filter cartridge is open 4 with molded gasket and the bottom is open 4 with molded gasket 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