Insulated Hand Tools from Jameson provide maximum electrical protection and are suitable for working live or close to live parts at nominal voltages up to 1,000 volts. Constructed using heavy-duty injection molded Nylon 11; the 12-in. Adjustable Hammerhead Wrench has a maximum jaw opening of 1-3/4 in. (45 mm) and is ideal for use in a wide variety of utility, electrical, and telecommunication applications.