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 Square Rulers also feature square-up diagonal lines with size indicators 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.