18" Clear Acrylic Quilting Ruler, Bias Bespoke Brand
18" long by 2" wide clear acrylic ruler with inch (Imperial/US) measurements. It's 1/8" thick, and the comparative inflexibility of the plastic (it doesn't bend) is a benefit for mark-making on fabric, since it helps to hold the fabric flat while marking, instead of allowing it to bunch under your chalk or pencil.