So Relative! If You Think I'm Good Looking, You Should See My Uncle Baby T-Shirt Romper (Yellow, 18 Months) Makes a great gift! Makes a great gift! Approximate sizing: 6 Months (12-18 pounds), 12 Months (18-25 pounds), 18 Months (25-30 pounds); 24 Months (30-34 pounds.) 100% pre-shrunk cotton Excellent quality, comfortable and fun.