The plastic used by Knipex will insulate against electrical current, but special requirements are needed for people who work on electrical systems. The standard blue-red handles on Knipex pliers will offer some insulation, but the “immersion insulation” included with the yellow-red handles on Knipex pliers meet these special requirements. In fact, every pair of insulated Knipex pliers are tested for 10,000 volts of dialectic strength as a final check before they’re put on the market.