Sumpsock | Poly Felt Filter Socks | Short, 8 &frac12;&rdquo; Length | 200 Micron | 4&rdquo; Diameter Ring | Aquarium | 5 Pack INCREASE WATER CLARITY & QUALITY: Felt filter socks are most commonly used to help collect and trap free floating debris, excess food and detritus, which in turn improves the water clarity and quality of your aquarium and the quality of life of your aquatic population, making them happier and healthier and contributing to longer lives. REMOVES PARTICLES EFFECTIVELY: A micron is a unit of measure in the metric system equal to 1 millionth of a meter in length. The human eye cannot see anything smaller than 40 microns in size. Since this felt filter is 200 micron rated, it will capture particles and contaminants that are the same size or larger than the width of a human hair. EASY TO CLEAN: You can wash your felt filter bag in a laundry tub using hot water and a little bleach. Simply wring it out, let it dry and reuse. These felt filter bags have the ability to be reused over and over again. Dont feel like washing the felt filter bag? No problem. Simply throw it away after it has been clogged and use one of the other four. Having a 5 pack will make it easier for you regardless if you reuse them or not. DURABLE MATERIALS: Our food grade felt is made out of polyester which is known to be a strong and flexible fabric that dries quickly. Solid construction with welded instead of stitched seams allow for extra strength and durability. Using this type of high quality mechanical filtration device helps to increase the overall life of your filter. CHOOSE CROSSCOURT COMMERCE: We are the go-to supplier of liquid strainers, bag filters and accessories. We offer a wide variety of products to bring ease and convenience into your life, in specialized areas of the market. Customer satisfaction is our number one priority, so please feel free to reach out to us with any questions or concerns that you may have.