I love my Bernina seam unsewer. Mine came with my machine, but you can go to a Bernina dealer and buy the unsewer (ripper is such a violent word!) without buying a new machine at the same time. Someone designed a quilting tool that includes a Bernina unsewer along with an awl. I would love to have that tool, but it is a bit pricey when I already have most of those tools individually (purchased before the designer tool came out.)