Klein Tools does not recommend using liquid rubber to repair the insulation on these tools. The insulation on these tools is designed to reduce risk of injury if the tools make contact with an energized source with voltage up to 1000 volts. All Klein insulated tools are clearly marked with the official 1000-volt rating symbol. Where marked, they meet or exceed the referenced ASTM F1505 and/or IEC 60900 standards for insulated/insulating tools, and comply with NFPA-70E and CSA Z462 standards for workplace electrical safety. The insulation on each tool consists of two layers. The high-dielectric white inner layer is thick, exceptionally tough, and bonded to the tool. The bright orange outer layer is flame-retardant and impact-resistant. Always inspect your tools before use. In addition to inspecting the tools before each use, ASTM F1505 recommends an annual visual examination by a suitably trained person to determine if the tools are suitable for continued service.