Poolmaster 12950 Replacement Filter Cartridge for Sundance Microclean 6540-501 Filter The corresponding Pleatco number is PSD85-2002 and the corresponding Unicel number is C-8380 The top of the replacement filter cartridge is closed with 2 male thread SAE 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