Does anyone know what the differences are between the Pibbs 514 with the purple labels around the knobs and the one with the orange/yellow labels? I have both and thought the orange/yellow labels were a newer model. However, I purchased another dryer, which I received today and it has the purple labels - now I am confused. At this point, I have purchased four of these dryers. I gave one away because I thought there was a newer model and one stopped working.