Dreamaxhp Truck Sleepwear Little Boys Cotton Pajama Set T-Shirt Pant Sets Size 1T:Recommended Age 3Months-1Years Size 2T:Age 1-2Years;Size 3T:Age 2-3Years;Size 4T:Age 3-4Years;Size 5T:Age 4-5Years and so on. If you would like a looser fit, room to grow or your child is really above the average, you will need to make your garments at least 1-2 sizes larger. Made of 100% Cotton, super soft. Machine wash with cold water and inside out.