Personalized Tuba Nut Toddler Long Sleeve T-Shirt. An acorn nut holding a sousaphone is a humorous musical instrument gift design to tickle the funny bone of low brass musicians in concert, tuba choir and marching band. 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.