Function: These expansion plugs are designed to winterize your swimming pool, protecting it from harsh winter conditions and potential damage. The tapered, rubber-covered plugs can be used to seal or block holes, pipes, drains, sinks, tanks, and more in your pool, kitchen, bathroom, or yard. Use as pipe plugs to seal skimmers, returns, and cleaner lines to prevent water from entering the plumbing during winter months. These expansion plugs can also assist in pressure testing pool lines, detecting leaks, 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: Light reflection and different display settings may cause slight variations in the color of the item shown. Measurement may vary by +/- 1-3cm.