Material is 100% polyester, no lining in romper, tie in the back, length is measured as shown how it is in picture, v neck Size small measurements: armpit to armpit is 16.5 inches, length (shown in pic 5) is 30.5 inches, waist is 12.5 inches. Medium: armpit is 17 inches, length is 31 inches, waist is 31 inches. Large: armpit 17.5 inches, length is 32 inches, waist 13.5 inches. All measurements are taken lying flat on the ground. Waist measurements are taken with the waist fully cinched.