Flux is a chemical cleaning agent that permits the flow of a brazing or soldering metal on a base surface at high temperatures. Some manufacturers sell brazing rods and brazing wire that contain flux in a hollow core or channel in the metal. The chalky white chemical is liquefied and deposited into the channel of the metal. The fill depth of the flux is measured using non-contact measuring principles in the AR200 laser measurement sensor. The tiny laser spot of the AR200 is focused onto the flux and not onto the walls of the metal wire.