Product packaging --- You will receive 2 swimming pool anti-freeze caps. Size: about 38mm. Material --- The winter plug is made of high-quality rubber, which has the largest expansion and good sealing performance and can be used for a long time. Excellent performance --- After the pool is drained, the rubber plug is used to block the pipe to prevent water from entering the pipe and causing freezing. Multipurpose --- Used as a rubber plug to block oil skimmer, return water and cleaning lines to prevent water from entering in winter. It is also possible to test the pressure of the pool pipe or stop the flow of water into the pool during equipment maintenance.