In addition to an adjustable on and off delay feature, the DRO allows the user to program set points, and has an adjustable filter to smooth out erratic flow conditions. The DRO flow sensor is designed to operate with media such as water, glycol and other fluids. It is a solid state device that operates on the calorimetric principle, and thus has no moving parts that can break or become lodged in the pipeline. DRO sensors are able to monitor changes in flow between 0.2 and 12 gallons per minute, and are available with a transistor, relay or analog output. They are manufactured with a standard eurofast M12 connector.