Poolmaster 12724 Replacement Filter Cartridge for Easy Clear CX-550 CX550RE Filter Equivalent to the following replacement filter cartridges; Pleatco PA55 and Unicel C-7455 The top of the replacement filter cartridge is open 3 molded gasket and the bottom is open 3 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