We’ve designed a safe and incredibly soft electric mattress pad that not only warms your bed, but also rejuvenates it. Two pads in one is the best way to describe this pad. The electric removable top 233 thread-count 80% poly/20% cotton dobby stripe decorative shell has six Velcro strips that attach to the bottom pad. It can be unhooked for washing or warm weather storage while leaving the bottom pad on the mattress for year round use. Constructed within the pad is the patented Safe & Warm low-voltage technology. This low-voltage pad 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 pad becomes wet. Unlike other warming pads with their thick bulky wires, the wires in the Soft Heat pads are so small, they are virtually unnoticeable. During construction we place the ultra thin wires 3-inches apart and evenly distribute them from head to toe. The benefit to you is a pad that gives more of an even heat and has no annoying hot or cold spots. The Cal king size pad is divided in two separate zones and comes standard with two easy to read, easy to turn, non-slip computerized controllers to adjust the temperature of each side of the bed giving individual comfort and control. For cozy sheets before bed time, it has an automatic pre-heat and hold feature. You simply turn it on and the pad 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. For your safety convenience and power conservation, it has an automatic shut off feature that will shut the pad off after 10 hours just in case you forget. It also comes standard with built in over-temperature protection for that extra bit of safety and peace of mind. On the controller, a giant backlit display with auto dimming feature provides more convenience for night time adjustments with out having to turn on the lights.