This water filter elements set is a replacement for Gravity Filtration System filter, have passed a high-standard examination by authoritative institutions, reduces chlorine, fluoride, heavy metals, taste and odor, sediments, particles and other harmful substances. Clean water can be enjoyed outdoors at any time. for Black Filter is made from materials, Compared with ordinary granular activated carbon, it has higher adsorption capacity, reduces fluoride and chlorine, filter impurities. for Fluoride and Reduction Elements replacement filters adsorb fluoride, (V) and pre-oxidized (III), and other residual typical heavy metal ions. This set of filter elements compatible with Gravity Filtration System filters, Compatible with FOR Super Sterasyl and Traveler, Royal, Big, Imperial and Crown Series. We recommend you replace for water filter every 1000 gallons and for black filter every 6000 gallons, to achieve performance, or you can replace it based on your water condition. Material: plastic colour: white+black Package Contents: 2 x for Water Filter 2 x for Water Filter