The Nature 2 I.G. replacement W28135 cartridge is designed to fit the Professional In-Ground units ( W25904 and W20011) easily and effectively lowers chlorine consumption. The Nature 2 technology uses silver and copper to sanitize your pool water lowering the chlorine necessary to keep your pool clean and clear saving you time and money.
* Designed to be used with the W25904 and W20011 for pools up to 35,000 gallons
* Simple and quick installation
* Lasts up to 6 months
* Lower your chlorine consumption by up to 50%