Keep drum contents warm and ready to roll. These dollies are often used for noncontact heating of thick, nonflammable, and nonhazardous materials such as wax. All have a time-cycle controller that constantly cycles on and off to keep your material warm. Turn the dial to adjust the ratio of on to off time. Since the controller has no built-in temperature sensor, it requires a thermometer (sold separately) to measure the temperature of the drum's contents to determine your desired heat setting.