The Eheim Double Tap Unit with Sealing Rings is designed to allow you to quickly and easily disconnect and connect your aquarium and filter hose safely without water backflow and flooding. The included sealing rings ensure an airtight, water-tight seal that permits you to swap out hoses or make adjustments without allowing any water to get through. You can create safe, functional hose connections with the Double Tap Unit for Professional Canister Filter that fits Eheim models 2026, 2028, 2126 and 2128. Remove any hosing from the canister without causing a flood or removing the hosing. This product is made with high-quality, long-lasting materials.