Inner Diameter 5/16" Outer Diameter 3/4" Overall Thickness 3/8" For Panel Thickness 1/8" For Panel Hole Diameter 1/2" Used to Insulate and seal around holes cut in solid panels Also Used to dampen vibration and minimize abrasion. Durometer hardness - 55A. Can be used indoors or outdoors. Color black. Flexible grommets made of SBR rubber Temperature range ?30° to +165° F.