The Dymax Stainless Steel Lily Pipe Set is perfect for maintaining proper aeration and water flow in your aquarium. Made from high-quality surgical-grade stainless steel, the pipes are resistant to rust, scratches, and calcium buildup. This set comes with both inflow and outflow pieces and is available in two sizes to fit different-sized aquariums. Additionally, it includes an aquarium surface skimmer attachment to keep the water's surface clean and free from debris and biofilm. The kit comes with one outflow lily pipe, one inflow lily pipe, and a surface skimmer attachment.