BSR is Bernina Stitch Regulator. It's for FMQ, with the BSR attached to the machine you get all stitches same length. At least that's the idea. I tried it once and as far as I can see it works.
I went to the dealer this afternoon and got the coverlock. Not the used one, I brought that one back. He told me I could put in my cupboard
I told him that he could do the same
Now I'm the proud owner of a Janome 100 cpx.