1. Protect your pool against the harsh winter season. A which prevents your pool from running into serious damage.2. Used as pipe plugs, to plug skimmers, returns and cleaner lines - to prevent water from entering the pipes during winter. Expansion plugs have other uses too, such as pressure testing pool lines or other methods of leak detection, or stopping water flow from the pool when equipment repairs are made.3. Heavy duty plugs made with stainless steel bolts, rubber compression body and are corrosion resistant. Made to work day in, day out. Will last you for many seasons.Specifications:Colour: blackMaterial: rubberSize: 5.08cmPackage Contents:1 * Rubber stopperOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.