These are vintage Singer sewing machine bobbins for class 15 series machines. The machines they fit are described as removable (oscillating) bobbin cases and top drop in bobbin cases. These are vintage metal bobbins and have the flat sides, NOT the slightly domed sides. We have photographed 5 of them but these may not be the exact 5 bobbins that you receive. We are selling 5 vintage bobbins at a time.