If you only buy one ruler for machine quilting, this is the one. It measures 10″x5″ and is 1/4″ thick for machine quilting. Combination straight edge and curved ruler. Quarter-inch, inch, and 45-degree markings as well as quarter-inch increment echo lines. Straight edge includes NeedleStops. Curved side is based on an 11-inch circle once sewn and has quarter-inch echo lines. This is a popular 2-in-1 ruler option that is great for beginners and seasoned longarm and domestic machine quilters. 'Ruler Work 101', by Michael Davison of Quarter Squared Quilt Co.