Here's a couple of the real things. The red one is to signify its in kilometres instead of miles like the black one. The red one dates from 1985 and the black one from 1973.
Stemco, a Texas based wheel end products manufacturer, took over Engler Instruments in the mid 80s and placed their oval symbol at the top in place of the "ei" Engler Instruments logo.
They carried on with the red for KM black for miles practise for a few more years before changing to a white face across the board which they are still making and see on truck trailers and some buses like in the picture.
Ahh, if only victa had kept producing the thumblatch catcher series, they would be in better shape today!
