For sale one Singer buttonholer model # 489510. $15. shipped. These are usually listed on Ebay and such as model # 489500 or 489510. The problem is that they are two different models. When listed like that its because the people don't know better and that its the instruction booklet that is the same and they are going by. I didn't know either untill I got this one thinking it would fit my 500 and 401 slant machines. It dosen't. I needed a 489500. So to be clear this is for straight presser foot shaft machines. I don't know if it matters for a short or long shaft machine. I couldn't try it but it looks to be like new. Has the buttonholer,feed cover plate,five templates,clamping screw and instruction booklet.