The invention provides an oscillator and a control method for controlling the oscillator which reliably oscillates even when the oscillator is driven at a low voltage. The second end of the flexible hose is connected to the handle portion, and the tubular wand is slidably mounted in the handle portion so as to be movable between a first position in which the tubular wand extends beyond the handle portion inside the flexible hose and a second position in which the tubular wand extends beyond the handle portion away from the flexible hose. The housing may include a headset wherein the GPS component is located, and a second housing component wherein the processor is located, wherein the GPS component communicates with the processor in a wireless manner. In one implementation, the present invention facilitates qualifying articles resulting from the process by comparing the desired versus observed value profiles for an indirect process variable.