Felt: Thicker, better at removing particles, but can clog faster
Plastic Ring: attaches via ring that fits Red Sea sump holders
Regular use will result in crystal clear water most convenient form of mechanical filtration.
Remove excess food, detritus, organic waste, dust and other particulates.
Prevents larger objects like sand, crabs, and snails from damaging pump motors
Reduces ammonia and nitrate producing organic waste
Increases filter life