Personalized Robot 6th Birthday Toddler Long Sleeve T-Shirt. Little robot 6th birthday I'M SIX Toddler Long Sleeve Tee - White with cute robot, stars and red planet with the number 6. A classic for Fall, Winter and Spring, these long sleeve toddler t-shirts are sure to be a staple in your child's wardrobe. Whether layered or alone, this t-shirt is soft yet durable enough to stand up to your toddler's playtime demands.