Nature2's Express (Inground) allows pool owners looking to reduce their chlorine consumption while still maintaining a healthy pool, simply by adding this self-contained sanitizing canister. Express installs on existing pool plumbing, making installation a cinch; while silver and copper compounds help sanitize your water to dramatically reduce chlorine usage. Lasting 6 months, this sanitizing canister will last practically one whole pool season, depending on where you live, and will save you significant time and money normally devoted to chlorine maintenance.