Good Measure Every Circle Machine Quilting Ruler Set by Amanda Murphy is a set of five 1/4" thick rulers to be used as guides for machine quilting. Circle set gives you 5 internal circle shapes in 1/2" increments. Internal circles let you quilt circles from 1/2" to 2-1/2". The five external circle shapes are in 1" increments. External circles let you quilt circles measuring from 3" to 7". Rulers have markings that clearly indicate the previous row's quilting lines, not found on other rulers! All have a non-slip backing.