Features Stainless steel screws and washers and large plastic wing-nuts. Safely seal off in-ground plumbing lines during freezing conditions. Winter Freeze connectors are used to connect pool tubes after they have been drained to prevent water from entering the freezing tubes and causing damage. We offer many sizes and styles to choose from, depending on your needs. Simply screw caps on return and drain inlets after blowing out lines. The rubber expansion plugs are non-corrosive high quality, durable, stainless steel, nylon, rubber construction. The wing nut turns easier and offers 50% more tightness than conventional plugs.