[3D Honeycomb Design Excellent Mechanical Filtering] 3D Woven Filter Socks Using 3D Textile Technology and Honeycomb Sandwich Structure Subversive Upgrade of Filter bag Industry. [4 inch Aquariums Filter Sock Hives are Designed]To Divert Water Mimic The way Bees Build Their Nests Contrasted with the past Aquarium Felt Filter Bags are Permeable Non-Clogging and Flexible Enough to be Flipped Over for Easy Cleaning. [To Create a Better Water Environment] characterized by interlocking micro felt fibers, the sump socks can catch food residues, fish waste, decaying plants, dust and other floating particles, which can improve the water quality in the tank. [Reliable Workmanship for Lasting Service] made of quality polypropylene, the 4 inch filter sock is tightly sewed, pliable and serviceable, which can be applied and washed for many times. [Three-Dimensional Weaving ] That Mimics The Nesting of Bees Filter Fabric Sock Multi-Functional Interlayer Filtration.