I saw no Js at all. I know the model number is correct, and it's the second one I've had with the C877 as the first set of numbers. I found a chart once that showed most of the numbered ones (158, 385, etc) but I've never seen this one referred to by a manufacturer name. I had to get a needle plate for a customer for the same model, but the replacement plate could fit almost all of the manufacturers (necchi, riccar, white, brother, etc) so it didn't narrow it down at all for me.
