Stainless steel heating element and aluminum fins. Painted 22 ga steel front with 20 ga junction boxes located on each end of the heater, junction boxes contain quick connect cable clamps and 6 in ground lead wires. Over-temperature thermal limit extends entire length of heated area. A full length wireway provided along the back of the heater. Safely installs with standard 60 deg C building wire. 240 V. UL listed. Thermostat sold separately.