Simple and effective biomechanical pre-filters improve pump performance. Prevents pump damage and flow reduction due to debris and clogs. Expandable units available in single or double Matala® filter media core for superior biological filtration. Universal barbed fittings accept 1" to 1-1/2" tubing or 1-1/2" MPT. The versatile EZ Bio Filter can be used as a biomechanical pre-filter for circulation pumps, filtration pumps, and water fountain pumps. The EZ Bio 20 has 2 filter core elements; an internal Gray core combined with a larger Green outer core element. The outer Green core element is 8 inch diameter and 7.5" long.