The mats protect people from harmful or deadly electrical shocks. Mats are made of a specially compounded non-conductive corrugated surface designed to prevent electric shock around high voltage electrical equipment. Tested to ASTM D178/ANSI J6.7 and certification is engraved on the back of each mat. Dielectric Test Voltage 30,000 VAC. Mats can be trimmed with a box knife for custom installations.