I just bought a Singer 136K104. Looks very much like yours, but with take-up/tension/check spring in the front. Bobbin seems the same.Crinkle paint. This model also seems to be "invisible". I can find manuals for 136W, which I suppose is "close enough," but nothing for 136K. Getting bobbins is insane. I order 136K and I get these enormous bobbins that I WISH my machine could take. Wish I could post a pic.