Standard Winter Expansion Plug
Winterizing plugs are also known as freeze or expansion plugs.
A simple design, these rubber plugs with two are used to prevent pool pipes from damage due to freezing. Unplugged pipes allow water to seep in and freeze during the off-season winter months, which can create extensive damage. These plugs are an inexpensive solution that prevent a potentially costly problem.
You can also use winterizing plugs to stop water flow from your pool when necessary for equipment repairs.