This is a genuine attachment for a vintage Singer sewing machine 
 
Singer sewing machine attachment.  Singer Simanco 36594
 
Binder Foot
 
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/36594/
 
The condition is shown in the photos.
 
There are two available for separate sale, they are both shown in the photos. Your item will be randomly selected from the available stock.