Function: These expansion plugs are designed to winterize your swimming pool, protecting it from damage caused by freezing temperatures and staining. The tapered plugs, made with rubber covering, can be used to seal or block holes, pipes, drains, sinks, and tanks in your pool, kitchen, bathroom, or yard. They are ideal for plugging skimmers, return lines, and cleaner lines to prevent water from entering the plumbing during winter. These plugs can also be used for pressure testing pool lines, leak detection, or stopping water flow during equipment repairs. Material: Rubber + Stainless Steel Color: Black Package Contents: 6 x Pool Plug (2 x 25mm, 2 x 38mm, 2 x 51mm) Note: Only the items listed above are included. Note: Light reflection and differences in display screens may cause slight variations in color between the product and the image. Measurement may vary by +/- 1-3cm due to manual measurement.