Thanks, precisionworks, for your detailed and fascinating history of Wilton vises in post #3 above.
I once owned a Wilton vise that I did not recognize in your listing of all the models they manufactured. Mine was unique in that it was a hydraulic vise. Its appearance was typical Wilton. I believe the jaws were 4.5" wide. You could recognize it from a distance because of its short cranking bar -- only six inches long, barely enough for a large hand to grasp. Turning this short bar offered no resistance at all until the jaws engaged, at which point there was slight resistance as the hydraulics came into play. This slight resistance would remain constant over one-half turn -- the full range of the hydraulics -- at which point it came to a full stop as the maximum clamping force of something like 2,000 lbs was reached.
I bought this vise new about 1960, plus or minus two or three years. It served me faithfully for several decades before the hydraulics failed. Wilton, having long since discontinued this model, was of no help towards repairing it. I don't remember its ultimate fate, but I still miss it to this day.