Well......
Hi Keith, This is what makes it somewhat difficult. The car I am putting them on is a 1964 Cadillac MM combo.......I know it sounds odd and maybe wrong to a lot of folks, but the Lewisville, MN Ambulance Service that last used the car had a set on it and I am restoring the car to look like it last did while in service. Being the holes are already there, I figuered if I could find a set, why not. The car was actually pictured on a web site based out of Canada dedicated to vintage ambulances when it was retired circa 1987. It was traded in to the Ringdahl Ambulance in Fergus Falls, MN and was pictured there in their lot. Its really neat to see a picture of my car from so long ago and the caption underneath says "Lewisville MN 1964 MM combo with superior lights". I can even buy a picture of my own car from them for five dollars.
Either way, they are the bullet style lense (large front, small rear) that stand up off the roof with a two bolt patterned contoured piece under the tunnel to fit the roof line. I believe the tunnel is made of fiberglass.