Thank you for all of your replies. There are monogrammers with round hoops like the one I posted and there are also oval hooped ones and I wasn't sure if there is a difference between them as to which machines they fit. I'm guessing as long as they have the mechanism under the throat plate, they'll work. I'll continue looking.
Miriam, there is a 3 page instruction pdf over on the Kenmore yahoo group if you need it.