Alaric Darconville
Flashlight Enthusiast
And those lenses were heated by the lit bulb.I do remember years (decades?) ago one long trip where I kept having to pull over to clean the halogen headlights in my old Scirocco because they kept getting dimmer and dimmer as the slush built up on them.
Another advantage the JW Speakers have over halogen is the lens is directly heated by a thermostatically-controlled defroster grid, so you only periodically have a small increase in power draw.