Antique Singer Treadle Sewing Machine Machine Lollypop Hinge.  This is the Single Screw Mount Hinge Variety.   This hinge attaches the sewing machine to the cabinet and allows it to be lifted up and then lowered back down. 

Photo is representative of the parts offered.  You are purchasing one  hinge and screw.     

Original Singer parts, with antique patina just as removed from the machines.   These are entirely serviceable and can be cleaned and/or restored to whatever level the new owner chooses.  Expect some surface rust, etc. as shown.  Original antique Singer part.