Used for water treatment, these 8mm Water Filtration Pebble, are a best choice as these water filtration. These pebble are made from hard, durable, sub-angular, and dense grains of predominately siliceous material. The impurities of water can be trapped within these pebble, while water is passed through it. The 8mm Water Filtration Pebble we are serving is finest and assured for quality, and tested thoroughly for its respective purposes. This product can be blindly trusted for using, and it does not give any chance of complaint even in the long run.