(It is the right model 15 1948 Singer Sewing Machine model 15.)
Singer Model 15 is a good machine. My treadle is a Model 15 and I love the stitch that it makes. From reading aroun on the web, it is one of the sturdiest home sewing machines that Singer has made. I've read that the only other machine that could beat it out would be a model 201. I haven't seen one, but I would love to try one out sometime.