"Vibrating Shuttle" instead of a round little bobbin that we are used to seeing, it is a barbell looking bobbin and goes into a shuttle that swing back and forth in an arc. It is the most soothing sound in the world listening to a VS machine sew!!!!
It is worth it in my book but it might be a little newer that it looks. They made that machine into the fifties, but it is in great cosmetic condition from the photos. Get the serial number from the seller and check out the date and how many machines were allotted for that run. It might be a low production run (the 128's were usually a low number run anyway) and worth even more.
Also it uses the standard 15x1 needles and the bobbins are readily available at Hancocks and possibly JoAnns in the notions section.
Billy