The Hayward replacement filter cartridge is designed for compatible StarClear II filter applications where the internal cartridge element needs replacement. A filter cartridge is useful because it traps suspended dirt and debris from the water, supporting cleaner water and dependable filtration-system performance.This replacement is especially useful when the original cartridge is torn, clogged beyond cleaning, collapsed, or no longer filtering effectively. Replacing the cartridge can help restore more dependable filtration and improve water clarity.The CX1100RE is a practical service part when a compatible Hayward StarClear II filter needs a cartridge to restore dependable filtration performance. Hayward StarClear II replacement filter cartridge Designed for compatible filter applications Helps trap dirt and debris for cleaner water Useful when the original cartridge is worn or clogged Supports cleaner and more dependable filter performance