Originally Posted by miriam
I think this is a WHATZIT
It appears to be an adjustable hemmer with one of the pieces missing.
It used to be a standard attachment, and is supposed to do folded hems. It wasn't as easy for me to get the hang of this one as it was to learn how to use the narrow hemmer.
I've always found it easier to me to press in a hem and then use a blind hem stitch. But, it still might be fun for you to play with this attachment, too. :)