Jiffy Jet washer bag question?

That looks so cool and original. It will certainly draw eyes at a car show. Watch the start of the 1963 movie "Lilies of the Field" next time on TV. Sidney Poitier first meets the nuns when his car overheats and he walks up w/ the coolant overflow bag for a refill. Might have been a special option for cars in the Southwest. Yours must have been in storage since few would last that long under-hood.