Be warm and comfortable. The indoor heater has a user-friendly design with 3 heating modes - 900W high, 400W medium and a cooling fan to set the optimum temperature for warmth on cold days and refreshing air on hot days. > Safety first. Our heaters use PTC ceramic heating technology and refractory materials to provide overheating protection as the heater shuts off when the temperature reaches 167 degrees. It also has a smart design that automatically shuts off when the heater is knocked over. Quick and Quiet: Thanks to advanced ceramic heating technology, this desk heater is energy efficient and provides heating faster, reaching temperatures of 70 degrees Fahrenheit in just 3 seconds! Don't worry, this heater has no light function and is very quiet, so you can sleep, read, study or take a nap without interruption. Portable and compact. The personal heater is very compact, measuring only 7.7 x 4.4 x 5 inches, but is also powerful and energy efficient, so you can use it to heat small