Filter Media Bag for freshwater & salt water use, it is made by high quality nylon, Special made to put activated carbon, bio ball, ammonia chips and other filtering material. Make your filter organize and easy to maintain Protect against damage caused by loose filter media Washable and reusable. (L) 300mmW x 360mmL Auction for 1 bag in packet i used mine to give you an idea of what it looks like in the picture for you start is reserve