Hayward's SwimClear Cartridge Filter is a high-strength, injection-molded durable glass reinforced copolymer tank holding 4 reinforced polyster cartridge filters.
Cartridge filters do not require backwashing and greatly reduce water consumption.  Cartridge filters effectively remove particles as small as 30 microns (beach sand is 1000 microns). And cartridge filters can handle much higher flow than sand filters, especially suitable for higher horsepower pumps.
The SwimClear C3030 has a filtration area of 325 square feet and a flow rate of 122 gpm.  The SwimClear C4030 is 425 sq ft and has a 150 gpm designed flow rate,.

Features:
  Self-aligned tank top and bottom for access
  Heavy-duty, tamper-proof, one-piece clamp
  1-1/2 inch or 2 inch plumbing
  Full sized 2 Inch internal plumbing for less resistance
  Visual indication when cartridges need to be cleaned
  Made from extra durable glass reinforced thermoplastic 
  High capacity rapid release manual air relief valve