Hayward® StarClear™ CX500RE 50 SqFt C500-Blue Replacement Cartridge Element. Hayward® replacement cartridges are manufactured with premium materials designed to meet NSFs high quality performance and durability standards. All Hayward® cartridges provide maximum hydraulic efficiency, exceptional first pass debris removal, extended filtration cycles, reduced cleaning time and multi-season durability., Clearly, Hayward Genuine Replacement Cartridges are the only replacement cartridges that will maintain the original filter fit and performance in addition to providing the best overall value.