This is a Singer Sewing Machine stripper, darning, embroidery and free motion spring action foot. It is #86294. It mounts on the needle bar, not the presser foot bar. This foot lets you sew all those special stitches. It will fit the old classics like the 27, 28, 127, 128, 66, 99 102. It will not fit machines like the 201 and the 15. Those machines have a larger diameter needle bar. This foot has a hole diameter of 7/32". It mounts with the thumb screw to the right side.