Oil-filled radiators are a type of portable heater that use oil as a heat reservoir. They contain a sealed chamber filled with oil, which is heated by an electric element. The oil retains heat and radiates warmth into the surrounding air, providing a steady and comfortable temperature. These radiators are known for their energy efficiency and ability to maintain warmth even after being turned off. They are often used in homes and offices to provide supplemental heating during colder months. Their design allows for even heat distribution, making them a popular choice for personal heating solutions.