I'm looking for these washers. I went to my local hardware store with no luck. I checked all the resource sites I have listed with no luck as well. LoveMySwitches has some similar, but the dimensions of his are not as good as these.
The dimensions are 20mm outer, 12mm inner and a=they are 0.5mm thick. I don't care if they are plastic, steel or aluminum. Any one?

I'm not sure from where this one came but it seems to be an oddball. But they are perfect for using with those large, bulbous colored aluminum stompswitch nuts. With those specific washers, I can bear down (tighten well) on those large stompswitch nuts without tearing into the water slide decal on the enclosure surface.