I always had a soft spot for those 4" round rubber-clad incandescent "trailer" lights. Or whatever they were called. Used to sell them for 3 to 4 bucks a piece back in the day, and they had a nice rugged appearance due to the rubber case.
They were not all that bright, nor did they have a great beam pattern. Nothing like a modern lamp of almost any description. But they were inexpensive even by the standards of the day, and were pretty much in every catalog and, literally, in bins by the bushel in hardware, auto parts, and just about any other general store you might think of.
Got a pair of them mounted up high on my camper shell. Still look cool to these older eyes!
Paul