Standard Skimmer dimensions around the outside of the faceplate 7.47"w X 7.18" h,
inside dimensions are 6.15"w X 5.62"h.
Wide-Mouth Skimmer features an extra-large opening for superb skimming action! Dimensions around the outside of the faceplate are 14 ¼" X 7 ¾", inside dimensions are 11 1/2" X 4 7/8".
Skimmers come with a gasket.