1. Superior material, strong bacteria culture capacity. It is a kind of filter material made by random winding and pressing of polymer plastic threads. The plastic thread is very thin, and after being wound randomly, formed a larger specific surface area. Therefore, it provides favorable conditions for the cultivation of nitrifying bacteria. 2. Strong water permeability The internal structure is connected by gaps and has high water permeability. Even if stacked in multiple layers, it will not affect the water circulation. 3. High density, more durable. Strong supporting force, high fiber density, not easy to deform, and long service life. Can be cut arbitrarily.