Used in CSI Nitro/Nitro Pro/SideKick and WaterSoft Centurion/Centuri/Sidewindr single tank aeration filters.  Aeration balls don't need to be replaced often, but if you are rebedding your filter with new media, you may want to add new aeration balls as well.  These can be used in any single-tank aeration filter.

25 pcs per pack.