The button foot!!
I've used the Pfaff foot many times & even read the Manuel on how to....laugh out loud! That particular foot allows you to place the button the the carriage so the machine makes the decision of measurement. Cool, right? I think so. I have yet to use the Janome foot & with hay season & my feelings of not wanting to sew these days.....sigh!
I'll be giving away a FQ so just leave a comment to be included in the drawing. Even if you've already won, you're still eligible.