What baby wouldn't look adorable in these fun rubber ducky pants! The material is a super soft, snuggle  100% cotton flannel. Has an elastic waistband for easy on and off. Size ChartSmall: 3-6 Months. Approx 7-13lbs with 13" side seamMedium: 6-9 Months. Approx 13-18lbs with 14.5" side seamLarge: 9-12 Months. Approx 18-21lbs with 16" side seamXLarge: 12-18 Months. Approx  21-27lbs with 17.5" side seam*NOTE: Each piece may differ slightly from the picture due to the repeat of the print*