the handle insulation material meets the requirements of IEC 900 and EN-60900 in terms of electrical strength and mechanical properties, adjustable wrenches are subjected to a high voltage test, the three layers of "plastisol" in different colors allow the user to easily check the state of the insulation, since that? Plastisol? Keeping the red color on the entire surface, safety is full and guaranteed, if an orange color appears in some places, the user must be careful because natural wearing has started, although the safety is still full and guaranteed once the color Is displayed in yellow, the user should immediately stop using the adjustable key as a safety tool for electrical installations and replace it with a new one, on the underside of the handle there is a fourth black layer (without electrical insulation properties), which provides additional protection against falls and bumps etc. in this area offers