This is a genuine attachment for Singer sewing machines.
 
Simanco sewing machine attachment.  Simanco 121464.
 
 
 
This is a genuine attachment for a vintage Singer sewing machine 
 
It is a robust metal foot binder, stamped Simanco 121464
 
Mechanisms work smoothly.
 
It measures approximately 5.8cm x 2.6cm. 
 
Fit the Binder to the machine in place of the standard foot and check the needle passes through the centre of the needle hole. Fold the binding in the centre and cut to a point. Insert the pointed end into the binder scroll until it comes out at the lower end. Place the edge of the material to be bound between the scroll of the binder and pass it and the binding under the presser foot, then lower the presser bar and start to sew. Folded binding should be inserted in the outside slot of the binder. The screw in the centre of the foot can be used to adjust the Binder for stitching to be at the desired distance from the edge of the binding, move the scroll to the right for narrower adjustment and to the left for a wider adjustment.
(http://www.singersewinginfo.co.uk/simanco/121464/)
 
The condition of the first item is similar to the condition shown in the photo. This is a stock photo. The second item has some metal pitting on the surface.