General description These expansion plugs are designed to winterize your swimming pool, protecting it from harsh winter conditions and potential stain damage. The tapered plugs, covered in rubber, can also be utilized to block or seal various holes, pipes, drains, sinks, tanks, and more in your pool, kitchen, bathroom, or yard. They serve as pipe plugs to prevent water from entering skimmers, returns, and cleaner lines during winter, and can be used for pressure testing pool lines or leak detection. Technical specifications Material: Rubber + Stainless Steel Color: Black Package Contents: 6 x Pool Plug (2 x 25mm, 2 x 38mm, 2 x 51mm) Measurement allowed error: +/- 1-3cm