Bumper Diameter 1" Height of Bumper 5/16" Stem Fits Hole Diameter 1/2" Ridge Diameter 11/16" Optimum panel thickness 3/16" Medium Hard abrasion resistant SBR Rubber Durometer Hardness is 55A to 65A Temperature range of –25° to +180° F. Material is non-marking. Screws not used for installation of this product Black SBR Rubber