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. Used to dampen vibration and minimize abrasion. Durometer hardness - 60A +/- 5. Can be used indoors or outdoors. Color black. Flexible grommets made of SBR rubber Temperature range -30° to +180° F.  New rounded shape.