BWT Water Pitcher Filter Replacement - 1 Filter + 3 Refills with Mg2+ A convenient package of one refillable water filter cartridge plus three refill packets. Fits perfectly into Brita pitchers. Uses innovative and unique Mg2+ technology that adds valuable magnesium to the filtered water and gives it a remarkable taste. Improves the quality of drinking water by removing chlorine, copper, lead, mercury and pesticides as well as limescale that damages kitchen appliances. Convenient and economical: refill your cartridges rather then throw them way: refillable cartridges can save you money. Environmentally friendly: refillable filters help to reduce waste as well as the use of water bottles, many of which end up in landfills.