Includes 6 black pool plugs in assorted sizes: 25 mm, 32 mm, 38 mm, 45 mm, 51 mm, and 63 mm. Durable construction: the winter pool plugs are made from stainless steel and PVC, providing stability in cold conditions, resisting slipping and shrinking, and enabling long service life. Function and compatibility: designed to be used as a tube plug to seal pool tubes in winter, helping prevent debris and cold air from entering the tubes; also suitable for enabling controlled outflow from the pool during equipment maintenance. Practical design: the plugs include expanded rubber components that seal pool tubes, and they are screwed into backwaters for secure sealing. Use scenarios: Winterizing pool lines to protect the plumbing during cold seasons. Sealing pipes during equipment maintenance to prevent leaks and control flow. Protecting pool piping during offseason storage or when the pool is not in use.