This time-saving closure device saves time and money when you winterize your pool. Simply replace your skimmer plate with the Aquador face plate and snap on the freeze-proof plastic closure. Your skimmer is now protected from freeze damage. Aquador eliminates the need for costly drain downs in the fall. Just place the Skimmer Guard into your skimmer to absorb any expansion caused by freezing water. The freezing water will actually compress the Skimmer Guard instead of expanding outward and cracking your skimmer. The bottom of the Skimmer Guard fits either a 1-1/2″” or 2″” internal thread