Hayward CX100XRE original 4 oz. filter fabric replacement cartridge fits the following filter model:
Hayward SwimClear Single Element C100S

This 4 oz fabric compared to comparable 3 oz fabric alternative cartridges will require less frequent cleaning and last longer

Specifications
Hayward original pool filter cartridge CX100XRE
Part number as seen on the filter cartridge end cap: CS100E (CS100-E)

Filter top and bottom ends are both open w/molded gasket and 4 inch inside diameter