The manufacture of rubber stopper Specification :20-B2 color: greyDiameter of the top part :19.5±0.2Diameter of the plug stem : 13.0±0.1Total height: 8.7±0.3Thickness of the top part :3.0±0.251.Reasonable design appearance 2.Moderate thickness for the pin-punching part 3.Heat-resistant and antioxidant