[High-efficiency Filtration] - This water filter elements set is a replacement for Gravity Filtration System filter, have passed a high-standard examination by authoritative institutions, Efficiently reduces chlorine, fluoride, heavy metals, taste and odor, sediments, particles and other harmful substances. Clean and healthy water can be enjoyed outdoors at any time. [for Black Filter] - for Black Filter is made from high-grade High-quality materials, Compared with ordinary granular activated carbon, it has higher adsorption capacity, efficiently reduces fluoride and chlorine, filter impurities. [for Fluoride Filter] - for Fluoride and Reduction Elements replacement filters adsorb fluoride, (V) and pre-oxidized (III), and other residual typical heavy metal ions. [Perfect Compatible] - 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: whiteandblack Package Contents: 2 x for Water Filter 2 x for Water Filter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is and or - 1-3cm.