Personalized Monster 1st Birthday Infant Romper. Cute 1st birthday Infant Romper - White with a funny cartoon purple monster, stars and polka dotted number 1 says THIS LIL' MONSTER IS ONE! Meet your new favorite outfit! Keep dressing simple with this one piece, lap shoulder t-romper. Super soft and perfect for baby's sensitive skin. 5.5 oz. 100% combed ringspun cotton premium jersey (CVC Colors are 60/40; Heather is 90/10 combed ringspun cotton/polyester)