This heated mattress pad earned The Best rating from the Hammacher Schlemmer Institute because it generated the most consistent warmth and was the most comfortable. The Best Heated Mattress Pad’s temperature fluctuated by only 1.08° F from top to bottom over eight hours, producing the most consistent temperature of any model tested. Panelists lauded The Best model’s soft cushioning, virtually undetectable heating elements, and soft, smooth cotton/polyester 200-thread-count fabric, resulting in the highest scores for comfort. Earning a perfect score for durability, The Best model did not shrink or fray after repeated machine washing. The Best Heated Mattress Pad’s superior features include dual LCD controllers on the King and Queen models that allow two sleepers to set their own temperature preferences from 5 heat settings and the heating elements shut off automatically after 10 hours. For mattresses up to 17" deep. Imported. Twin. 39" W x 75" L.