Features 1. Material: The winter expansion plug is made of high-quality rubber material and stainless steel bolts, which are reliable, stable, rust resistant, not easy to break, and durable. 2. Function: The design purpose of the antifreeze plug in the swimming pool is to block the swimming pool pipeline after drainage, preventing water from entering and causing icing. 3. Easy to Use: Simply screw the plug into all return and drain ports, making it easy to operate and use without too much effort. 4. Usage: Used as a pipe plug to block skimmers, return pipes, and cleaning pipes to prevent water from entering the pipes during winter. 5. Multifunctional: This plug can also be used for pressure testing of pool pipelines or other leak detection methods, or to prevent pool water from flowing out. Specification Material: Rubber Plug Size: 25 mm, 32 mm, 38 mm, 45 mm, 51 mm, 63 mm Color: Black Size: 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 Weight: 31 g, 48 g, 65 g, 83 g, 100 g, 120 g Package Include: 1x Expansion Plug