(Allied Precision) Made durable and break resistant of high impact plastic material. Unique "ribbed" design on bottom side eliminates "hot spots" by leaving air space, yet won't collapse to pinch heating element. Can be used alone or covered with Allied's Heat Mat Cover. Can be used indoors or out. Heats to approx. 98-100º, will not fluctuate. Contains built-in thermostat to heat at constant temperature. Fully grounded and cord is wire covered for safety. 120 volt.Heat mat should only cover 1/2 of the area it is used in.