The Aquasure Premier Series 4th Stage Quick Twist Alkaline Remineralizing Filter is a high-quality water filtration cartridge designed by Aquasure. Specifically designed for the Premier Series models, this filter is capable of providing clean and safe water for an extended period of time, with a cartridge life of 6 months. Alkaline filters like this one help to remineralize water, making it ideal for those who want to ensure their drinking water is not only clean but also rich in essential minerals.