Skimmer faceplate measures 18-1/4" wide x 8-1/4" high and inner opening dimensions 15-1/8" x 5-5/8". This time-saving closure device saves money when winterizing pools. Simply replace your skimmer plate with the Aquador face plate (requires phillips head screwdriver) and snap on the freeze-proof plastic closure. Your skimmer is now protected from freeze damage. With Aquador; there's no need for costly water drain downs in the fall. The Aquador stays flexible to -80 degrees.