4" x 8" 200 Micron Felt Filter Sock
200 Micron Filtration - filters well while also being able to go longer between changes.
Standard 4 inch ring - made of high quality thick plastic unlike other socks that use inferior plastics. Fits all 4" filter sock holders.
Polyester Felt material - using felt as a filter sock material has it's advantages such as removing micro bubbles from your overflow. Micro bubbles won't pass through the felt material as they would a mesh material.