Inner Diameter 1/4" Outer Diameter 3/4" Overall Thickness 7/16" 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.