Double-Duty Switchboard Anti-Fatigue Mats. This unique non-conductive anti-fatigue mat features a premium Nitricell sponge base, mait it first in class for mfort and safety. • nfor to ANSI/ASTM D178 01, Type II, Class 2. • These mats can insulate against as much as 40,000 volts of electricity. • Available 5/8" thick.