This is a Vinyl Inlet Face Plate Gasket This is Used on the Hayward SP-1408 Inlet and Others There is a Center Hole With a Notch and 4 Outside Holes Outside Diameter: 3-3/8" Center Hole Diameter: 2-5/32" Outside Hole Diameter: 3/16" The Outside Holes Are 2-1/2" Apart From the Opposite Hole. This Is Measured at the center line