Infrared replacement glass panel for TEC® RadiantWave™ grills. One glass panel is used per ccoking zone (AKA burner / control knob).(Later Sterling and Sterling FR, including the G series grills use 84790 HW0407 panels - see related items.)One RadiantWave™ glass panel is just under 14 inches square. If you hold a TEC® infrared glass up to a cool white flourescent light the light looks like a darkening orange sunset. The lower photo shows it with a 6V lantern battery flashlight behind. (And unfortunately, a reflection of the flourescent light on the ceiling.)This is a special order item and may take several weeks to get it in. (TEC® no longer makes the RadiantWave™ grill and has only a limited supply of the glass panels left for them.)78939 is TEC® part number HW0411.