Delta wrap-around drum heaters are designed with durable spring-loaded toggle clamps to ensure high clamping pressure, while being flexible enough for one person to attach and remove. Delta drum heaters are adjustable for normal drum dimension variation. Multiple heaters may be applied to a single drum for quicker or unusual heating requirements. Heaters are constructed of rust- and corrosion-resistant stainless or galvanized steel. The unit is designed to allow quick transfer of such viscous materials as tar, adhesive, chocolate, molasses, paraffin, tallow, various petroleum products, etc., from standard 55, 30, or 5 gallon steel containers. Availability of two different types of controls permits the user to fit the heater to a specific application. This is important, because various materials have different heat transmissions and reaction characteristic. Neon pilot light indicates when the unit id on. Each heater includes compact contoured control box, improved clamping hardware, and an attached 6-foot power cord with an optional three-conductor plug for grounding.