I purchased mine very inexpensively a few years ago. I love it.
When I use it on my Pfaff 7570 I put the plastic spool adaptor on my upright spindle then the deelybop so it has something flat to rest on. I then put on the spool - I use the spools of
signature cotton thread for all my piecing. I also use the smaller deelybop for the thread with the carboard centers and that works great. I have not used the "washers" for anything.
I use this on my babylock quilters pro also.