Rubber Hole Plug for 1 3/8" Opening -- 1 3/4" Diameter Rubber Grommet Without a Hole -- Hard To Find Item -- Has 1/16" groove around outer circumference -- For Installation in 1/16" Thick Panel Can be used to seal hole in panel or create your own hole in center for custom application - For Panel Hole Diameter 1 3/8" Overall Thickness 7/16" For Panel Thickness 1/16" Durometer hardness - 55A. Can be used indoors or outdoors