Whipstitch's 3.5" by 18" Fat Quarter Ruler features markings every 1/8", with a diagonal line at 45 degrees on either end for easy half-square triangle trimming. As the name suggests, this ruler is ideal for trimming fat quarters. These Fat Quarter Rulers are laser cut and engraved from 1/8" acrylic. Plus, with the markings being engraved, you never have to worry about the numbers or lines coming off. To help prevent your ruler from shifting, non-slip dots are included with each ruler.