Greist manufactured buttonholers long before Singer. Evidently Singer was rather late in adding buttonholers to their line up of attachments. If you compare the Greist buttonholer to the old Black Singer buttonholers, you will find that they are remarkably similar (almost identical). They still work beautifully and are my favourite way to make buttonholes as they are always exactly the same. You can't beat those old cams! I even use my old buttonholer on my Janome 6500 as it does a much better job and will handle larger or thicker buttonholes.