Material: The winter expansion plug is made of high-quality rubber and stainless steel bolts, offering reliable, stable, rust-resistant performance that is durable and not prone to breakage. Function: Designed to block swimming pool pipelines after drainage, this freeze plug prevents water from entering and causing ice damage. Easy to Use: Simply screw the plug into return and drain ports for quick, effortless installation with no additional tools required. Usage: Acts as a pipe plug to seal skimmers, return lines, and cleaning lines during winter months to prevent water intrusion. Multifunctional: Suitable for pressure testing pool piping systems or detecting leaks, and helps prevent pool water from draining out. Specifications: Material: Rubber Plug Sizes: 25 mm, 32 mm, 38 mm, 45 mm, 51 mm, 63 mm Colors: Black Dimensions: 4 x 3 x 3 cm, 4 x 4 x 3 cm, 5 x 4 x 3 cm, 6 x 4 x 4 cm, 6 x 5 x 4 cm, 7 x 6 x 5 cm Weights: 31 g, 48 g, 65 g, 83 g, 100 g, 120 g Package Includes: 1 x Expansion Plug Note: Due to differences in lighting and screen settings, the actual color may vary slightly from images. Slight dimensional variations may occur due to manual measurement.