Its inch-marked edge and tight curve are key features of the 12" curve ruler. It also has a few basic illustrations printed right on it for quick reference while you're working. The ruler's small curve is perfect for adjusting armholes & necklines. Beginner techniques include changing the shape or size of a collar, adjusting pockets or raising/lowering a neckline. Intermediate sewists can decrease a sleeve cap or adjust the crotch curve in a pair of pants.