SpinAbout Rectangle Rulers by QuiltCut allow you to work in whole-inch or half-inch increments easily. Add a 1 2 seam allowance to your cuts by spinning the ruler around 180°. The SpinAbout Rulers are screen printed on high quality 1 8 thick acrylic and have a non-slip coating to prevent slippage when cutting by applying slight pressure but will still glide over the fabric when spinning about. The translucent dual-colored markings provide superior visibility when working with light or dark materials. Easy view invisiline™ windows allow you to see the edges of your fabric perfectly for precise placement. The SpinAbout Rectangle Rulers also feature 30°, 45°, and 60° angled lines to cut triangles and alignment lines for fussy cutting. You will find 1 grid lines that include primary markings for 1 4 , 1 2 , and 3 4 measurements, as well as secondary markings for 3 8 and 5 8 measurements. The SpinAbout Rulers feature numbering for both right-handed and left-handed users. Made in the USA.