Feature:<br /><br />\u25cfThe products include Volcanic stone \/ ammonia ecological stone \/ activated carbon \/ bio-beads \/ ceramic rings  six kinds of filter material. You can choose one.<br />\u25cfFive kinds of filter materials, comprehensive filtering, improve water quality, purify water, inhibit algae, stable PH value, remove sterilization, in addition to the stench, accelerated nitrification colony forming.<br />\u25cfPromote fish metabolism and expel harmful substances from the body. Effectively increase the amount of oxygen dissolved in the water. Removal of harmful heavy metals in water.<br />\u25cfCan be extended water changes time.<br />\u25cfMaintain the water clear.<br />\u25cfRendered neutral PH value, will not change the water quality.<br /><br />Product Attributes: <br /><br />Material: Biological Filtering Material<br />Color: As picture shown<br />Weight: About 196g<br />Quantity: 1 Pcs<br />Model: 1#-Volcanic Stone<br />             2#-Ammonia Ecological Stone<br />             3#-Activated Carbon<br />             4#-Bio-beads<br />             5#-Ceramic Rings<br /><br />Package Include:<br /><br />1 x Biological Filtering Material<br /> <br />Note:<br /><br />1.Due to the light and screen difference, the item's color may be slightly different from the pictures. Please understand. Make sure you don't mind before you bid.<br />2.Size just for reference. Please allow few differences due to manual measurement.