Gave mine away as the first one went haywire and crumpled in the bobbin holder.

Mine did that before I took the metal tension disc out of the bobbin case.

The repairman that cleans and repairs my machine said the washers stop static. That is their purpose. Metal spinning in metal will cause static. I'm happy using them but they are sure hard to find when dropped. LOL

I have them, but my quilting is horrible. My mother says to be patience and keep practicing.

I have tried them on several machines and I think they work best if you have a metal bobbin in a metal bobbin casing. Also if you already have a bobbin spring inside your bobbin case they aren't necessary as the bobbin springs do the same thing. :) I have yet to need one on my drop in bobbin machines, and as a matter of fact they seem to create more of a problem for me in my drop in machines than the others.

Just tried one in my Brother machine. My stitches went really tiny (The setting is for 2.5 stitch length)I set it at 4.5 (usuallt a basting stich). My stitches were still really tiny. Took out the washer, stitches are now fine.