LTWHOME Compatible Filtration Foam Fit Rena Filstar xP Filter Media 723A 20PPI(Pack of 12) These foam filter pads are the ideal thickness to filter small waste particles. Custom designed and manufactured for the Rena Filstar Filtration Systems. Enhances biological filtration. Provides efficient water flow with less clogging for long lasting filtration. Good for freshwater and saltwater environments.