Good Measure by Amanda Murphy - Set of 5 Circles. Allows you to make any circle perfectly. Made for Domestic & Long arm machines. All with non-slip backing.  
This set of five rulers helps stitch circles ranging in size from 1/2” to 7”.  The measurements on the rulers are those of the stitched circles.  There are many markings on these rulers, making them easy to use for many quilting applications.