You may not believe this - I still find it hard to, but I had been watching an ebay auction for 5 W&W 9 bobbins. The photos showed they were the bagel or donut type. After 31 bids, they sold last night for $255.00 and $5.35 shipping. So I went to look an see how many of those bobbins were in my wooden box of attachments. I have eight of them!
Anyway, I know they are hard to find but never would have thought they were that valuable.