"June Tailor Shape Cut". It's 18" square with slots every 1/2", making it possible to cut strips of any width. I got mine a couple of years ago at walmart in quilting notions area. I think you can find them in Joann, Hancock, or most other shops.
Good Luck - By the way, I know a lot of quilters love to use them, but I hardly ever use mine - old habits die hard. I bought it after seeing Eleanor Burns use it on Alex Anderson's show.