This is a set of three dies that cut semi-circles, with a stitched line on the inner and outer edges. The sizes of the domes are approximately: 3.75 x 2.66, 3.125 x 2.22, and 2.37 x 1.67 inches. The dies cut the shapes shown and work with many of the popular die cutting machines such as the Big Shot, Spellbinders Platinum, Gemini, and more.