I need an appropriate part name... It's not my car, but my girlfriend's car. Her 2006 Cobalt sedan LT has a broken HVAC fan speed knob. I tried ebay, it wouldn't find anything. So I'm wondering if anyone know the correct part name or even number for the HVAC fan speed?

The one right in the middle between the cold/hot temp and selection on defrost/defrost-floor/floor/floor-vents. Ya know...

Much thanks in advance!