... design Low noise Dynamic Compact Semiconductor Fan Heater, Industrial Electric Air Heater, CSL 028, 150W,250W,400WCompact designLow noiseDynamic ... F)Operating / Storage humiditymax. 90 % RH (non-condensing)Protection type / Protection classIP20 / II (double insulated)ApprovalsUL File No. E150057 ... with UL508A Compact Semiconductor Fan Heater, Industrial Electric Air Heater, CSL 028, 150W,250W,400W