The thing I don't like about this tool is: you can't put the cover on the back end of the ripper so you have both things in your hand at the same time.
It won't fit on the end of the Seam Fix ripper because it's a safety issue.
I don't use the ripper part of the Seam Fix. It's not sharp or thin enough for me. I just buy it for the eraser end. Cheap at Walmart.