Serta Luxe Plush low voltage Blanket was designed with one thing in mind: To be the best, most comfortable and safest blanket that you will ever own! Constructed within the blanket is the patented Safe & Warm low-voltage technology. This blanket includes a small power supply box that changes 120 volt AC home current into non-hazardous low-voltage DC current (very similar to a battery) to provide warmth, protection and safety even if the blanket becomes wet. An automatic pre-heat and hold feature makes sure that your bed is warm and cozy before you climb in for the night. You simply turn it on and the blanket will warm up on HI until it reaches the temperature that you pre-set your dial on and then adjusts itself to hold it there. It also comes standard with built in over-temperature protection for that extra bit of safety and peace of mind.