Quilter's Select Square It, 8.5"This unique ruler is perfect for squaring up or centering traditional quilt blocks, applique blocks and machine embroidered blocks and features the unique Non Slip Coating. The inner area of the ruler has a 6. 5 x6. 5 in opening with measurement markings from center out. The outer edge measures 8. 5x8. 5 in with traditional left to right measurement markings. All measurements in 1 4 in increments.