... Air Heater, CSL 028, 150W,250W,400W Compact design Low noise Dynamic Compact Semiconductor Fan Heater, Industrial Electric Air Heater ... % RH (non-condensing)Protection type / Protection classIP20 / II (double insulated)ApprovalsUL File No. E150057 (according to UL 499, intended ... the use within an enclosure in accordance with UL508A Compact Semiconductor Fan Heater, Industrial Electric Air Heater, CSL ...