Temperature-controlled cable runs straight along pipe and valves, held in place by application tape and plugs into grounded electrical outlet. Keeps water flowing down to -380. For odd lengths of pipe over 3/4 inches in diameter, we recommend two separate cables on opposite sides of the pipe with up to 3 feet of overrun at center of pipe run. Metal pipe requires 1/2-inch fiberglass insulation around cable. For plastic pipe, its recommended wrapping pipe with aluminum foil before cable installation. The traditional resistance cable produces a fixed amount of heat based on the electrical line feed. It comes with a built-in thermostat that switches the flow of electricity on and off based on temperature. Cable installs fast and easy. Each package contains grounded plug, built in thermostat and instructions. Cable has weather resistant PVC outer jacket and inner insulation. Keeps water flowing down to 40 F.