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 e: 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