Sweater is knit flat in 3 sizes: Newborn, 12 mos. & 18 mos. Adjustments to size are made by adjusting needle size or yarn (to get 3 different gauges.) You may use any DK or sport weight yarn that knits to gauge. If you would like to make a solid colored sweater, allow 4 (50 gram) balls of yarn to be on the safe side. If you would like to make a striped sweater you’ll need one ball each of 5 colors.