This Clamshell template set (2 templates) is sized to work nicely with 10-inch pre-cut squares. Our patent-pending Slit 'N SewTM method represents a truly revolutionary improvement by allowing curved piecing to be done quickly and easily each and every time! Using the CutRiteTM Slit 'N Sew templates, simply use a rotary cutter to make small cuts that are precisely located on the templates. Then proceeding a slit at a time, line up the next slit from each piece that is being pieced together and sew to that slit. The result? A perfect curved piecing job in no time! No tedious and time-consuming pinning! No paper piecing! May be performed by quilters of all skill and experience levels. Works for non-curved shapes such as diamonds and tumblers - just match the slits and the points line up automatically! Ideally sized to work with standard pre-cuts, such as 5 in and 10 in squares, or use with other fabric that you have. Easy to see fluorescent green acrylic color! Includes CutRiteTM HandiGrabber material to keep template securely in place.